Description:DESCRIPTION:
Field of the invention:
[0001] The present disclosure generally relates to the technical field of green nanotechnology, and in specific relates to development of plant-mediated bimetallic gold-palladium nanoparticles (Au-PdNPs) for anti-inflammatory and therapeutic uses.
Background of the invention:
[0002] Nanotechnology is an emerging field of research, and nanobiotechnology is gaining significant interest due to its ability to develop nanosized materials from biological origins for various applications. Metal nanoparticles bimetallic nanoparticles (Au-PdNPs), have been extensively studied for their unique properties, including biocompatibility, chemical stability, and low toxicity. These nanoparticles are widely applied in medicine, biology, chemistry, and physics, with increasing attention in biomedicine, pharmacy, and bioscience. Among them, Au-Pd core-shell bimetallic nanoparticles are considered highly effective nanocatalysts due to their enhanced structural, electrochemical, and catalytic properties.
[0003] Despite the advantages of metal nanoparticles, conventional synthesis methods rely on chemical and physical processes that are expensive, environmentally hazardous, and involve toxic reagents. These methods often produce nanoparticles with unpredictable size distribution and stability, limiting their effectiveness in biomedical and catalytic applications. The need for eco-friendly, cost-effective, and biologically safe alternatives to synthesize metal nanoparticles remains a significant challenge in nanotechnology.
[0004] Several methods have been developed to synthesize bimetallic nanoparticles. Chemical reduction methods use strong reducing agents like sodium borohydride or hydrazine to produce nanoparticles. Physical methods employ laser ablation, sputtering, or electrochemical deposition to generate nanoparticles. Microbial and plant-based green synthesis use biological systems like bacteria, fungi, or plant extracts to synthesize nanoparticles in an eco-friendly manner.
[0005] However, chemical reduction method involves hazardous chemicals that pose environmental and health risks. The resulting nanoparticles may also contain residual toxic substances, limiting their biomedical applications. High-energy consumption and expensive equipment make these physical methods impractical for large-scale production. While promising, the microbial synthesis requires strict sterile conditions and extended processing times, making it less efficient. Although safer and eco-friendly, many plant-mediated methods lack optimization for rapid and controlled nanoparticle formation, leading to variable sizes and stability issues.
[0006] Therefore, there is a need for development of plant-mediated bimetallic Au-Pd nanoparticles (Au-PdNPs) for anti-inflammatory and therapeutic uses. There is also a need for an eco-friendly, non-toxic biosynthesis of metal nanoparticles using Sarcolobus carinatus plant extracts.
Objectives of the invention:
[0007] The primary objective of the invention is to provide biosynthesis of bimetallic Au-Pd nanoparticles (Au-PdNPs) using Sarcolobus carinatus that eliminates the need for toxic chemical reagents, making the process environmentally sustainable.
[0008] The other objective of the invention is to provide nanoparticles that are synthesized at room temperature with significantly reduced reaction times, improving process efficiency.
[0009] The other objective of the invention is to provide bioactive compounds such as alkaloids, flavonoids, tannins, and saponins enhances the stability and potential biomedical applications of the nanoparticles.
[0010] Another objective of the invention is to provide nanoparticles that exhibit high optical activity, making them suitable for biomedical imaging, diagnostics, and catalytic applications.
[0011] The other objective of the invention is to provide synthesized nanoparticles that are characterized by controlled shapes (spherical, triangular, and hexagonal) and small average particle sizes, enhancing their applicability in nano-medicine.
Summary of the invention:
[0012] The present disclosure proposes a method for green synthesis of Bimetallic Gold-Palladium nanoparticles using sarcolobus carinatus. The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
[0013] In order to overcome the above deficiencies of the prior art, the present disclosure is to solve the technical problem to provide development of plant-mediated bimetallic Au-Pd nanoparticles (Au-PdNPs) for anti-inflammatory and therapeutic uses.
[0014] According to an aspect, the invention provides a method for synthesizing nanoparticles (NPs). First, a fruit paste is boiled in water through a bain- marie method. The boiled fruit paste is then filtered to prepare an aqueous fruit extract of Sarcolobus carinatus. Next, the aqueous fruit extract of Sarcolobus carinatus is mixed with an aqueous solution at a ratio of 1:6 to obtain a nanoparticles mixture. The aqueous solution comprises a combination of 1mM chloroauric acid (HAuCl₄.3H₂O) and 2mM palladium chloride (PdCl₂). Next, the nanoparticles mixture is incubated at room temperature for a required time period to formulate the bimetallic nanoparticles (Au-PdNPs). In one embodiment, the nanoparticles (NPs) are formulated as an injectable, topical, or oral pharmaceutical composition for inflammatory conditions.
[0015] In one embodiment, the nanoparticles mixture is incubated at room temperature for a time period of at least 15 minutes to obtain bimetallic gold-palladium nanoparticles (Au-PdNPs). In one embodiment, the synthesized Au-PdNPs exhibit a surface plasmon resonance peak at 532 nm. The synthesized Au-PdNPs are synthesized at pH 4 to 12 and remain stable for at least 37 days at room temperature and 4°C.
[0016] In one embodiment, the bimetallic nanoparticles comprise a palladium core and a gold shell, upon the synthesis of the bimetallic nanoparticles using HAuCl₄·3H₂O and PdCl₂ in a ratio of 1:2. The bimetallic nanoparticles comprise a gold core and a palladium shell, upon the synthesis of the bimetallic nanoparticles using HAuCl₄·3H₂O and PdCl₂ in a ratio of 4:1.
[0017] Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.
Detailed description of drawings:
[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, explain the principles of the invention.
[0019] FIG. 1 illustrates a flowchart of a method for synthesizing bimetallic gold-palladium nanoparticles (ScF Au-PdNPs), in accordance to an exemplary embodiment of the invention.
[0020] FIG. 2A illustrates a graph depicting optimization of bimetallic gold-palladium nanoparticles (ScF Au-PdNPs) synthesis conditions, in accordance to an exemplary embodiment of the invention.
[0021] FIG. 2B illustrates a graph depicting effect of salt ratio on ScF Au-PdNPs synthesis, in accordance to an exemplary embodiment of the invention.
[0022] FIG. 2C illustrates a graph depicting effect of time at a room temperature (0-day 30) at RT, in accordance to an exemplary embodiment of the invention.
[0023] FIG. 3A illustrates a graph depicting effect of temperature on ScF Au-PdNPs Formation, in accordance to an exemplary embodiment of the invention.
[0024] FIG. 3B illustrates a graph depicting effect of Sarcolobus carinatus fruit extract concentration, in accordance to an exemplary embodiment of the invention.
[0025] FIG. 3C illustrates a graph representing the effect of pH variation (pH 4 to pH 12) on the synthesis of the ScFAu–PdNPs, in accordance to an exemplary embodiment of the invention.
[0026] FIGs. 4A – 4E illustrate the effect of salt concentration and pH on the synthesis of the Au–PdNPs, in accordance to an exemplary embodiment of the invention.
[0027] FIG. 5A illustrates a FTIR spectra of the SCF fruit extract, in accordance to an exemplary embodiment of the invention.
[0028] FIG. 5B illustrates a FTIR spectra of the synthesized Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0029] FIG. 6A illustrates a Raman spectral for Raman spectroscopy analysis of the synthesized Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0030] FIG. 6B illustrates a XRD pattern of the synthesized Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0031] FIG. 6C illustrates field emission scanning electron microscopy (FESEM) image of AuPdNPs, in accordance to an exemplary embodiment of the invention.
[0032] FIG. 6D illustrates an EDX spectrum of the synthesized ScF Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0033] FIG. 7A illustrates a HR-TEM image of the ScF Au-PdNPs at 50 nm, in accordance to an exemplary embodiment of the invention.
[0034] FIG. 7B illustrates a distribution histogram of the ScF Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0035] FIG. 7C illustrates SAED pattern of the ScF Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0036] FIG. 8A illustrates a zeta potential distribution graph of the ScF Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0037] FIG. 8B illustrates a dynamic light scattering (DLS) particle size distribution graph of the ScF Au-PdNPs, in accordance to an exemplary embodiment of the invention.
[0038] FIGs. 9A - 9D illustrate comparative effects of various green-synthesized nanoparticles and extracts on % membrane stabilization and hemolysis inhibition, in accordance to an exemplary embodiment of the invention.
[0039] FIGs. 10A – 10C illustrate effect of green-synthesized nanoparticles and extracts derived from SCF on the inhibition of protein denaturation, in accordance to an exemplary embodiment of the invention.
[0040] FIGs. 11C – 11D illustrate corresponding pseudo-first-order kinetic plots indicating the reaction rate constants for each catalyst, in accordance to an exemplary embodiment of the invention.
[0041] FIGs. 12A-12C illustrate UV-Visible absorption spectra showing peak reduction at regular time intervals under solar exposure, in accordance to an exemplary embodiment of the invention.
[0042] FIGs. 12D-12F illustrate plots of ln(Aₜ/A₀) versus time, showing pseudo-first-order reaction kinetics, in accordance to an exemplary embodiment of the invention.
Detailed invention disclosure:
[0043] Various embodiments of the present invention will be described in reference to the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps.
[0044] The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present invention to provide development of plant-mediated bimetallic ScF Au-Pd nanoparticles (Au-PdNPs) for anti-inflammatory and therapeutic uses.
[0045] According to an exemplary embodiment of the invention, FIG. 1 refers to a flowchart 100 of a method for synthesizing nanoparticles (NPs). At step 102, a fruit paste is boiled in water through a bain- marie method. The boiled fruit paste is then filtered to prepare an aqueous fruit extract of Sarcolobus carinatus. At step 104, the aqueous fruit extract is mixed with an aqueous solution at a ratio of 1:6 to obtain a nanoparticle mixture. The aqueous solution comprises a combination of 1mM chloroauric acid (HAuCl₄.3H₂O) and 2mM palladium chloride (PdCl₂). At step 106, the nanoparticle mixture is incubated at room temperature for a required time period to formulate the bimetallic nanoparticles (ScF Au-PdNPs). In one embodiment, the nanoparticles (NPs) are formulated as an injectable, topical, or oral pharmaceutical composition for inflammatory conditions.
[0046] In one embodiment, the term bimetallic nanoparticles as used herein refers to bimetallic gold-palladium nanoparticles, ScF Au-PdNPs, and Au-PdNPs and may be interchangeably used in the specification to denote the same class of nanoparticles.
[0047] In one embodiment, the nanoparticles mixture is incubated at room temperature for a time period of at least 15 minutes to obtain bimetallic gold-palladium nanoparticles (Au-PdNPs). In one embodiment, the synthesized ScF Au-PdNPs exhibit a surface plasmon resonance peak at 532 nm. The synthesized ScF Au-PdNPs are synthesized at pH 4 to 12 and remain stable for at least 37 days at room temperature and 4°C.
[0048] In one embodiment, the bimetallic nanoparticles comprise a palladium core and a gold shell, upon the synthesis of the bimetallic nanoparticles using HAuCl₄·3H₂O and PdCl₂ in a ratio of 1:2. The bimetallic nanoparticles comprise a gold core and a palladium shell, upon the synthesis of the bimetallic nanoparticles using HAuCl₄·3H₂O and PdCl₂ in a ratio of 4:1.
[0049] According to another exemplary embodiment of the invention, FIG. 2A refers to a graph 200 depicting optimization of ScF Au-PdNPs synthesis conditions. The synthesis is carried out using varying extract-to-salt ratios varies between 1:1 and 1:14. The optimum conditions for Au-PdNPs synthesis are determined to be 1:6 (extract to 1mM salt) at room temperature (RT) with 15 min of incubation. The colour development is observed as purple, indicating the formation of bimetallic ScF Au-PdNPs. A characteristic peak at 532 nm is recorded, with a maximum absorbance of 0.893. The purple colour formation confirms the successful reduction of HAuCl₄.3H2O and PdCl₂ salts by biomolecules in the plant extract, leading to the synthesis of ScF Au-PdNPs. The absorption peak at 532 nm is indicative of the Surface Plasmon Resonance (SPR) effect of gold nanoparticles, confirming their presence in the bimetallic structure. The absorbance intensity (0.893) suggests efficient nanoparticle formation at the optimized 1:6 ratio, making it the best condition for further studies.
[0050] According to another exemplary embodiment of the invention, FIG. 2B refers to a graph 202 depicting effect of salt ratio on ScF Au-PdNPs synthesis. The reaction is conducted with varying ratios of plant extract to salt, ranging from 1:1 to 1:14. As the salt volume increased, the intensity of the purple colour deepened, suggesting enhanced nanoparticle formation. UV–VIS spectrophotometry, conducted in the 300 to 700 nm range, confirmed an increase in SPR peak intensity with rising salt concentrations. Higher salt concentration provides more metal precursors (HAuCl₄.3H2O and PdCl₂), leading to a higher nanoparticle yield. The increase in SPR peak intensity correlates with the growth in particle size and number. However, excessive salt concentration may lead to aggregation or poly-dispersity, affecting the stability and uniformity of nanoparticles. The 1:6 ratio is determined to be optimal, achieving a balance between particle formation and stability while minimizing excessive aggregation.
[0051] The reaction is monitored over time intervals (0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and up to 30 days) at RT. After 2 hr, the reaction initiated, developing a pale lavender colour with an absorbance of 0.136 at 539 nm (λmax). Over time, the colour intensified, and both absorbance and peak wavelength increased. By day 30, the absorbance reached 0.642, indicating an increase in nanoparticle size and number.
[0052] According to another exemplary embodiment of the invention, FIG. 2C refers to a graph 204 depicting effect of time at a room temperature (0-day 30) at RT. The gradual increase in absorbance and shift in λmax suggests a continuous growth phase of ScF Au-PdNPs over time. The initial pale lavender colour indicates the early formation of small nanoparticles. As the reaction progressed, nanoparticles increased in size and concentration, leading to higher absorbance and wavelength shifts. This prolonged nanoparticle growth suggests that the biomolecules in the extract provide sustained reduction and stabilization.
[0053] According to another exemplary embodiment of the invention, FIG. 3A refers to a graph 300 depicting effect of temperature on ScF Au-PdNPs Formation. The reaction is studied at different temperatures varies between 40 °C and 90 °C. A slight variation in absorbance is observed at a temperature of 90 °C. The wavelength remained constant at 535 nm, while absorbance varied from 0.497 to 0.574 across the temperature range. An increase in temperature led to a reduction in reaction time, indicating that nanoparticle formation occurred more rapidly at elevated temperatures. This acceleration is attributed to enhanced reaction kinetics, which promote the faster reduction of metal ions. The consistent surface plasmon resonance (SPR) wavelength observed at 535 nm suggests that temperature variations do not significantly affect the size or structure of the synthesized nanoparticles. A slight increase in absorbance at higher temperatures may be due to accelerated nucleation and growth. However, excessive heating beyond an optimal threshold can lead to nanoparticle instability or aggregation, indicating that room temperature offers the most favorable conditions for stable synthesis.
[0054] According to another exemplary embodiment of the invention, FIG. 3B refers to a graph 302 depicting effect of Sarcolobus carinatus fruit extract concentration. The reaction is conducted with different extract volumes varies between 0.1 mL and 0.5 mL. An increase in extract concentration resulted in higher absorbance values ranging from 0.196 to 0.306 and a slight red shift in the λmax from 529 nm to 532 nm. The corresponding deepening of color intensity indicates enhanced nanoparticle formation. A greater volume of plant extract introduces more biomolecules such as polyphenols and flavonoids, which facilitate faster and more efficient reduction of metal ions. The rise in absorbance suggests a higher yield of nanoparticles with increasing extract concentration. The minor shift in λmax implies that while nanoparticle formation is enhanced, there is no significant change in particle size or distribution. However, excessively high extract concentrations may lead to over-capping of nanoparticles, potentially altering their physicochemical properties, underscoring the importance of maintaining an optimal extract concentration range.
[0055] According to another exemplary embodiment of the invention, FIG. 3C refers to a graph 704 representing the effect of pH variation (pH 4 to pH 12) on the synthesis of the ScFAu–PdNPs, further optimizing the nanoparticle formation environment. While increasing pH from 4-9 the λmax is increased from 532-533 by 1hr which is gradually decreased with increasing Abs till 5hrs with the λmax 527-529nm. From pH 10-12 at 1hr the λmax is reduced from 532-525nm which is increased gradually along with absorbance for 5hrs with λmax from 527- 528nm.
[0056] According to another exemplary embodiment of the invention, FIGs. 4A – 4E refer the effect of salt concentration and pH on the synthesis of the ScF Au–PdNPs. FIG. 4A illustrates a graph 3500 depicting the effect of increasing PdCl₂ concentration (1 mM to 5 mM) at a constant 1 mM concentration of HAuCl₄·3H₂O, corresponding to the molar ratios of 1:1, 1:2, 1:3, 1:4, and 1:5. FIG. 4B illustrates a graph 3502 depicting the effect of increasing PdCl₂ concentration (1 mM to 5 mM) at a fixed 2 mM concentration of HAuCl₄·3H₂O, i.e., salt ratios of 2:1, 2:2, 2:3, 2:4, and 2:5. FIG. 4C illustrates a graph 3504 showing the salt concentration effect for a constant 3 mM HAuCl₄·3H₂O with PdCl₂ ranging from 1 mM to 5 mM, forming the combinations 3:1, 3:2, 3:3, 3:4, and 3:5. FIG. 4D illustrates a graph 3506 depicting similar salt concentration ratios using 4 mM HAuCl₄·3H₂O combined with 1 mM to 5 mM PdCl₂, yielding ratios 4:1 to 4:5. FIG. 4E illustrates a graph 3508 depicting salt concentration ratios for 5 mM HAuCl₄·3H₂O with increasing PdCl₂ concentrations from 1 mM to 5 mM (ratios 5:1 to 5:5).
[0057] A systematic study is conducted to evaluate the effect of varying concentrations of bimetallic salt precursors on the synthesis of ScF Au–PdNPs. The optimization is performed by maintaining a constant extract-to-metal salt solution ratio of 1:6. The effect of varying concentrations of palladium(II) chloride (PdCl₂) in the range of 1 mM to 5 mM is assessed while keeping the concentration of hydrogen tetrachloroaurate(III) trihydrate (HAuCl₄·3H₂O) fixed at 1 mM. Similarly, further sets of combinations were studied by maintaining fixed concentrations of HAuCl₄·3H₂O at 2 mM, 3 mM, 4 mM, and 5 mM, and varying the PdCl₂ concentration from 1 mM to 5 mM, yielding a total matrix of salt ratios: (1:1, 1:2, 1:3, 1:4, 1:5), (2:1, 2:2, 2:3, 2:4, 2:5), (3:1, 3:2, 3:3, 3:4, 3:5), (4:1, 4:2, 4:3, 4:4, 4:5), and (5:1, 5:2, 5:3, 5:4, 5:5).
[0058] Additionally, reciprocal optimization is performed by keeping PdCl₂ constant and varying HAuCl₄·3H₂O concentrations from 1 mM to 5 mM, following a similar matrix. To the best of our knowledge, this is the first reported optimization study of bimetallic salt ratios for nanoparticle synthesis using the ScF extract derived from mangrove species.
[0059] UV–Visible spectroscopy confirmed the core–shell nature of the synthesized bimetallic nanoparticles. At a salt ratio of 1:2 (HAuCl₄·3H₂O:PdCl₂), formation of nanoparticles with palladium core and gold shell is observed, whereas at a reverse ratio of 4:1 (PdCl₂:HAuCl₄·3H₂O), a gold-core/palladium-shell configuration is indicated. These spectral observations support the formation of tunable bimetallic nanostructures through salt concentration modulation.
[0060] In one embodment, the study uniquely reports, for the first time, the method of optimizing bimetallic salt concentration for the green synthesis of ScF Au-PdNPs. Furthermore, the anti-inflammatory activity of the synthesized ScF Au–PdNPs (bimetallic nanoparticles) is evaluated and found to be effective even at an ultra-low concentration of 0.5 µg, as summarized in Table 3. A low-concentration efficacy for bimetallic nanoparticles in protein denaturation and membrane stabilization assays is achieved, highlighting potent bioactivity and potential therapeutic relevance.
[0061] According to another exemplary embodiment of the invention, FIG. 5A refers to a FTIR spectra 500 of the SCF fruit extract. FIG. 5B refers to a FTIR spectra 502 of the synthesized Au-PdNPs.
[0062] The SCF fruit extract is found to contain various bioactive phytoconstituents including alkaloids, carbohydrates, cardiac glycosides, coumarins, flavonoids, glycosides, proteins, phytosteroids, quinones, and reducing sugars. These biomolecules are believed to play critical roles in the reduction and stabilization (capping) of metal ions during nanoparticle synthesis. FTIR spectroscopy is employed to identify the functional groups involved in the bioreduction and capping of the ScF-Au-PdNPs. FIG. 5A shows the FTIR spectrum of the SCF extract, while FIG. 5B corresponds to the synthesized bimetallic ScF Au-Pd nanoparticles.
[0063] A comparative analysis revealed multiple shifts in characteristic absorption peaks, indicating interaction of functional groups during nanoparticle formation. The O–H stretching vibrations from alcohols showed a shift from 3971 cm⁻¹ (extract) to 3964 cm⁻¹ (Au-PdNPs), while additional O–H peaks at 3694, 3663, 3624, and 3601 cm⁻¹ in the extract shifted to 3644 cm⁻¹, suggesting involvement of phenolic groups. A shift from 3574 cm⁻¹ to 3584 cm⁻¹ corresponds to N–H stretching vibrations of amide groups, indicating protein participation. The peak at 3390 cm⁻¹ shifted to 3351 cm⁻¹, attributed to C–H stretching in phenolic compounds. The peak at 2942 cm⁻¹ shifted to 2925 cm⁻¹, associated with C≡C triple bond (alkyne), and 2904 cm⁻¹ to 2853 cm⁻¹, linked to C–H stretching. The peak at 2037 cm⁻¹, indicative of C–H bonds, shifted to 2016 cm⁻¹ in the nanoparticles. The characteristic C=O and N–H bending vibrations observed at 1639 cm⁻¹ in the extract shifted to 1641 cm⁻¹ in the Au-PdNPs. A peak at 1062 cm⁻¹ shifted to 1017 cm⁻¹, associated with C–C stretching vibrations from alcohols. Aromatic C=C stretching vibrations originally observed at 677, 553, and 521 cm⁻¹ in the extract were shifted to 951, 481, 443, and 430 cm⁻¹ in the nanoparticles, indicating the presence of aromatic compounds.
[0064] The disappearance of certain peaks from the SCF extract in the FTIR spectrum of the Au-PdNPs confirms the active involvement of specific functional groups in the reduction and stabilization processes during nanoparticle formation.
[0065] According to another exemplary embodiment of the invention, FIG. 6A refers to a Raman spectral 600 for Raman spectroscopy analysis of the synthesized ScF Au-PdNPs. The prominent peak of ScF Au-PdNPs at 1561, 1324 in the raman spectrum were caused by ring Nitro & carboxylate, the medium bands, at 1042, 1829, 2333 were attributed to moderate C-C aliphatic chain, moderate anhydride, and weak P-H the low peaks of ScF Au-PdNPs at 784, 685,487, 358, 167.83 were attributed to C-Cl, C-Br, S-S,C-C-Aliphatic chain.
[0066] According to another exemplary embodiment of the invention, FIG. 6B refers to a XRD pattern 602 of the synthesized Au-PdNPs. The XRD pattern 602 of the synthesized ScF Au-PdNPs, as shown in FIG. 6B, exhibited distinct diffraction peaks at 2θ values of 38.19°, 44.35°, 64.70°, 77.70°, and 81.76°. These peaks can be indexed to the (111), (200), (220), and (311) crystallographic planes, respectively, of a face-centered cubic (FCC) structure. The diffraction pattern matches the standard reference data from JCPDS card no. 04-0784, confirming the FCC crystalline structure characteristic of both gold and palladium. The (111) reflection appeared as the most intense peak, indicating a preferred orientation and suggesting that the (111) facet is the dominant growth direction. This also confirms the crystalline nature of the synthesized nanoparticles.
[0067] Additional minor peaks may be attributed to organic moieties derived from the plant extract, which likely acted as reducing and capping agents during the synthesis of the SCF-Au-PdNPs. The average crystallite size of the nanoparticles is calculated using the Scherrer equation, and is found to be approximately 11.9 nm, further supporting the formation of nanoscale particles with FCC structural characteristics. Similar XRD profiles have been reported for nanoparticles synthesized using Ananas comosus (pineapple) extract, reinforcing the observed diffraction characteristics.
[0068] According to another exemplary embodiment of the invention, FIG. 6C refer to field emission scanning electron microscopy (FESEM) image 604 of ScF AuPdNPs.
[0069] According to another exemplary embodiment of the invention, FIG. 6D refers to an EDX spectrum 606 of the synthesized ScF Au-PdNPs. The EDX spectrum 606 of the synthesized ScF Au-PdNPs confirms the elemental composition of the bimetallic nanoparticles. A prominent peak at approximately 5.38 keV corresponds to both gold (Au) and palladium (Pd), verifying their presence as the major metallic constituents in the sample. Quantitative elemental analysis revealed that gold constituted 63.3% and palladium 11.3% of the total elemental composition. In addition, carbon (29.45%), oxygen (8.4%), and trace levels of chlorine (Cl) were also detected. The presence of carbon and oxygen is attributed to the phytochemical capping agents originating from the SCF extract, which facilitated the reduction and stabilization of the nanoparticles.
[0070] These findings are consistent with previously reported EDX profiles of bimetallic nanoparticles synthesized using Emblica officinalis (Amla), Terminalia belerica (Bahera), and Terminalia chebula (Harad) extracts, which similarly showed nanoparticle sizes in the range of 40–70 nm and significant metallic content.
[0071] According to another exemplary embodiment of the invention, FIG. 7A refers to a HR-TEM image 700 of the Au-PdNPs at 50 nm. FIG. 7B refers to a distribution histogram 702 of the Au-PdNPs. FIG. 7C refers to SAED pattern 704 of the ScF Au-PdNPs.
[0072] The HR-TEM images 3100 shown in FIG. 7A confirm that the ScF Au-PdNPs exhibit diverse morphologies, including spherical, triangular, and hexagonal nanoparticles. These images 3100 were analyzed using ImageJ software. The corresponding particle size distribution histogram (FIG. 7B) revealed a size range of 5–45 nm, with an average particle size of 15.3 nm. These results are in line with previously reported green-synthesized bimetallic Au-Ag nanoparticles prepared using tea powder extract, which also demonstrated polydispersity and similar morphological features. However, this is the first report of green-synthesized Au-Pd bimetallic nanoparticles utilizing Syzygium cumini fruit (SCF) extract, marking a novel contribution to the field of eco-friendly nanomaterial synthesis.
[0073] Referring to FIG. 7C, the SAED pattern 704 displayed bright circular rings that were indexed with Miller indices and matched with standard diffraction planes of face-centered cubic (FCC) structures of gold and palladium. The observed planes at (111), (200), (220), and (311) confirm the crystalline nature and FCC structure of the synthesized bimetallic Au-Pd nanoparticles.
[0074] According to another exemplary embodiment of the invention, FIG. 8A refers to a zeta potential distribution graph 800 of the ScF Au-PdNPs. FIG. 8B refers to a dynamic light scattering (DLS) particle size distribution graph 802 of the ScF Au-PdNPs.
[0075] FIG. 8A illustrates the zeta potential distribution graph 800 of the ScF Au-PdNPs, revealing a zeta potential value of −12.6 mV. This negative surface charge is attributed to capping by phytochemicals present in the SCF extract, such as amino acids, flavonoids, alkaloids, and glycosides, which act as both reducing and stabilizing agents during nanoparticle synthesis. The obtained value closely correlates with previously reported zeta potential of bimetallic Pd–Pt nanoparticles synthesized using Peganum harmala L, which exhibited a zeta potential of −12.7 ± 2.1 mV. This investigation represents the first report of zeta potential measurements for green-synthesized bimetallic Au–Pd nanoparticles, providing key insights into their surface stability and electrostatic repulsion behavior in colloidal systems.
[0076] The dynamic light scattering (DLS) analysis, depicted in FIG. 8B, confirmed that the synthesized ScF Au-PdNPs were polydisperse, with a Z-average hydrodynamic size of 336 nm and a polydispersity index (PDI) of 0.15. The DLS profile further supports the stabilizing effect of plant-derived biomolecules on nanoparticle dispersion, indicating acceptable colloidal stability.
[0077] According to another exemplary embodiment of the invention, FIGs. 9A - 9D refer to comparative effects of various green-synthesized nanoparticles and extracts on % membrane stabilization and hemolysis inhibition.
[0078] FIG. 9A refers to a graph 900 depicting effects of the ScF Au-PdNPs, and Diclofenac sodium on % membrane hemolysis inhibition. FIG. 9B refers to a graph 902 depicting effects of Hexane extract of SCF, Ethanolic extract of SCF, and Diclofenac sodium on % membrane hemolysis inhibition.
[0079] FIG. 9C refers to a graph 904 depicting effects of the ScF Au-PdNPs, and Diclofenac sodium on % membrane stabilization of HRBC. FIG. 9D refers to a graph 3306 depicting effects of Hexane extract of SCF, Ethanolic extract of SCF, and Diclofenac sodium on % membrane stabilization of HRBC.
[0080] Referring to FIGs. 9A – 9D, the results demonstrated that ScF Au-PdNPs exhibited superior membrane stabilization potential, significantly reducing red blood cell (RBC) lysis under heat-induced stress. The bimetallic Au–Pd nanoparticles showed the most effective hemolysis inhibition, suggesting synergistic bioactivity attributed to the combined metallic composition and phytochemical capping agents from the SCF extract. Both hexane and ethanolic SCF extracts exhibited moderate activity, while Diclofenac sodium served as a positive control for comparative reference.
[0081] In one embodiment, anti-inflammatory activity of green synthesized nanoparticles of aqueous extract of Sarcolobus carinatus Au-PdNPs, Hexane and Ethanol is estimated by the Protein Denaturation method and HRBC assay with the Diclofenac Sodium as the Standard drug with the slight modification reference. To conduct HRBC membrane stabilization assay, blood (5ml) from a healthy volunteer who did not intake nonsteroidal anti-inflammatory drugs (NSAID) for 6 months. The blood is mixed with an equal volume of alsever solution (20.5g dextrose,8g sodium citrate,0.55g citric acid, and 4.2g sodium chloride in 1000ml water) the total volume mixture is centrifuged at 3000 rpm for 15 mins. Washed thrice with isosaline solution and the obtained packed cell is used for the Assay. In one embodiment, the assay mixture contains the aliquot of 500µl HRBC suspension, 0.15M phosphate buffer (1ml) with pH7.4, 0.36% hyposaline solution (2ml), and 500µl sample. Then, the mixture is incubated at 37c for 30 min in incubator, after 30 min incubation the suspension is centrifuged at 3000 rpm for 20min. Diclofenac sodium and deionized water are used as positive and negative control. The haemoglobin content present in the supernatant is evaluated by measuring the absorbance at 560nm by UV-VIS spectrophotometer. The percentage HRBC membrane stabilization is calculated as follows: Inhibition (%) = 100-(OP/OD) *100.
[0082] Different concentrations of (0.5µg-100µg) Au-PdNPs hexane and ethanolic extracts of SC (0.5mg-100mg), Diclofenac sodium is taken as a standard with both (0.5µg/ml-100µg/ml and 0.5mg/ml-100mg/ml) are taken and to this 500µl of blood, 1ml of phosphate buffer, 2ml of hyposaline are added and mixed thoroughly and incubated at 37c for 30 min and then placed in centrifuge for 20 min at 3000 rpm. The supernatant is collected and examined through UV-VIS spectroscopy at 560nm.The samples are done triplicates.
[0083] According to another exemplary embodiment of the invention, FIGs. 10A – 10C refer to effect of green-synthesized nanoparticles and extracts derived from SCF on the inhibition of protein denaturation, which serves as an in vitro indicator of anti-inflammatory activity.
[0084] FIG. 10A refers to a graph 1000 depicting effects of the ScF Au-PdNPs, and Diclofenac sodium on the inhibition of protein denaturation. FIG. 10B refers to a graph 1002 depicting effects of Hexane extract of SCF, Ethanolic extract of SCF, and Diclofenac sodium on the inhibition of protein denaturation FIG. 10C refers to a graph 1004 depicting effects of the Au-PdNPs, and Diclofenac sodium on the inhibition of protein denaturation.
[0085] FIGs. 10A – 10C, display the effect of green-synthesized nanoparticles and SCF extracts on protein denaturation inhibition, a standard in vitro marker for anti-inflammatory activity. Similar to the hemolysis assay, the ScF Au-PdNPs demonstrated the highest inhibitory effect on thermally induced protein denaturation.This inhibition suggests strong protein stabilization potential, indicating significant anti-inflammatory properties. The SCF hexane and ethanolic extracts exhibited moderate inhibition, while Diclofenac sodium showed high inhibition, consistent with its known pharmacological profile. These findings collectively confirm the anti-inflammatory potential of the ScF-mediated nanoparticles, with bimetallic Au-PdNPs emerging as the most potent among the tested formulations.
[0086] According to another exemplary embodiment of the invention, FIGs. 11A – 11B refer to UV-Vis spectra (1100, 1102) showing reduction in peak intensity for methylene blue in the presence of NaBH₄ and SCF Au-PdNPs (25 µg/mL) over time.
[0087] According to another exemplary embodiment of the invention, FIGs. 11C – 11D refer to corresponding pseudo-first-order kinetic plots (1104, 1106) indicating the reaction rate constants for each catalyst.
[0088] SCF Au-PdNPs (25 μg/mL) achieved 98% degradation for 27 mins. With a rate concentration of 25 μg/mL SCF AuNPs. In addition, the smaller size of ScF Au-PdNPs (15.5 nm) may enhance scattering efficiency and catalytic activity. Previous studies on MB degradation using AuNPs synthesized from plant extracts (Sesbania grandiflora and Solieria tenuis) reported that the efficiencies of 80%–97% at 1–9 mg concentrations. With a rate concentration of 25 μg/mL SCF AuNPs showed 95% degradation with a rate constant of 1.373 × 10⁻¹ min⁻¹in 21 mins, while SCF AuPdNPs achieved 94% degradation with a rate constant of 1.29 × 10⁻¹ min⁻¹ in the same duration. The low degradation efficiency of SCF Au-Pd NPs may be due to Pd masking by Au or a lower Pd content, as indicated by EDS analysis. The highest is observed for SCF Au-PdNPs superior catalytic activity at significantly lower concentrations (12.5–25 μg/mL), highlighting their potential for efficient pollutant degradation in environmental applications.
[0089] According to another exemplary embodiment of the invention, FIGs. 12A – 12C refer to UV-Visible absorption spectra (1200, 1202, 1204) showing peak reduction at regular time intervals under solar exposure. The degradation efficiency is evaluated at three different nanoparticle concentrations include 25 µg/mL, 50 µg/mL, and 100 µg/mL. The graph provides a comparative analysis of the catalytic potential of the individual and bimetallic nanoparticles, demonstrating how their efficiency varies with concentration.
[0090] According to another exemplary embodiment of the invention, FIGs. 12D – 12F refer to plots (1206, 1208, 1210) of ln(Aₜ/A₀) versus time, showing pseudo-first-order reaction kinetics. SCF Au-PdNPs at 100 µg/mL achieved a degradation efficiency of 94% with a rate constant of 4.45796 × 10⁻¹ h⁻¹.
[0091] SCF Au-PdNPs (FIGs. 12A – 12C) displayed degradation efficiencies of 47%, 82%, and 94%, with corresponding pseudo-first-order rate constants of 2.49896 × 10⁻¹ h⁻¹, 4.19796 × 10⁻¹ h⁻¹, and 4.45796 × 10⁻¹ h⁻¹ (FIGs. 12D – 12F) The enhanced degradation observed in Au-PdNPs may be attributed to the synergistic effect of Au and Pd, which further leads to an optimal catalytic activity. A previous study on Au-PdNPs synthesized from Tamarix gallica leaf and stem extracts reported 89% of MB degradation within 48 hours using 3 mM gold and palladium salt precursors whereas Bimetallic SCFAu-PdNPs shown 94% of degradation efficiency which is significant at 100μg.
[0092] Numerous advantages of the present disclosure may be apparent from the discussion above. In accordance with the present disclosure, a development of plant-mediated bimetallic Au-Pd nanoparticles (Au-PdNPs) is disclosed for anti-inflammatory and therapeutic uses.
[0093] Biogenic gold-palladium nanoparticles (Au-PdNPs) have gained significant attention in nanotechnology due to their lower toxicity and eco-friendliness compared to chemically synthesized nanoparticles. These nanoparticles can be synthesized using biological sources such as plants, fungi, and bacteria. In one embodiment, Sarcolobus carinatus aqueous extract is utilized for the biosynthesis Au-PdNPs, which exhibited SPR peaks 532 nm, indicating successful nanoparticle formation. These nanoparticles demonstrated good stability at room temperature without additional energy sources.
[0094] FTIR spectroscopic analysis confirmed that hydroxyl and amino functional groups played a role in the biosynthesis and stabilization of ScF Au-PdNPs. Zeta potential measurements indicated surface charges of -10.3 mV (Au-PdNPs), suggesting moderate stability. The polydispersity index (PDI) values are 15.0% (Au-PdNPs), while their hydrodynamic sizes 336 nm, respectively, indicating moderate dispersion. Structural analysis through SEM and EDS confirmed the morphology and elemental composition of the nanoparticles. HRTEM analysis, along with ImageJ software, determined the nanoparticle sizes as Au-PdNPs: 15.3 nm.
[0095] Furthermore, XRD spectral analysis confirmed the crystallite structures of these nanoparticles. The anti-inflammatory activity of the biosynthesized ScF Au-PdNPs, along with hexane and ethanolic fruit extracts of Sarcolobus carinatus, is evaluated using the protein denaturation assay and HRBC membrane stabilization assay, with Diclofenac sodium as the reference standard. Results showed that ScF Au-PdNPs exhibited the highest anti-inflammatory potential. In the protein denaturation assay, the IC50 values are ScF Au-PdNPs: 623 µg/mL, Standard Diclofenac sodium: 67.88 µg/mL, Hexane extract: 254 mg/mL, and Ethanolic extract: 289 mg/mL. In the membrane stabilization assay, ScF Au-PdNPs exhibited the highest membrane stabilization of 29.7% at 10 µg/mL, surpassing the standard Diclofenac sodium (25.8%). These findings indicate that biosynthesized Au-Pd nanoparticles possess significant anti-inflammatory properties, making them potential candidates for therapeutic applications.
[0096] The biosynthesis of bimetallic Au-Pd nanoparticles (ScF Au-PdNPs) using Sarcolobus carinatus eliminates the need for toxic chemical reagents, making the process environmentally sustainable. The nanoparticles are synthesized at room temperature with significantly reduced reaction times (ScF Au-PdNPs in 15 min), improving process efficiency. The presence of bioactive compounds such as alkaloids, flavonoids, tannins, and saponins enhances the stability and potential biomedical applications of the nanoparticles. The nanoparticles exhibit high optical activity (with surface plasmon resonance 532 nm for Au-PdNPs), making them suitable for biomedical imaging, diagnostics, and catalytic applications.
[0097] The synthesized nanoparticles are characterized by controlled shapes (spherical, triangular, hexagonal) and small average particle sizes (ScF Au-PdNPs: 15.5 nm), enhancing their applicability in nano-medicine. XRD and Zeta potential analyses confirm the crystalline structure and stability of the nanoparticles, with surface charge values of -12.6 mV (ScF Au-PdNPs), indicating good colloidal stability. The bimetallic Au-PdNPs demonstrated the highest anti-inflammatory activity, in protein denaturation and HRBC membrane stabilization assays. The high bioactivity of these nanoparticles, particularly in anti-inflammatory applications, suggests their potential use in drug delivery, wound healing, and inflammatory disease treatment. The catalytic properties of ScF Au-PdNPs make them suitable for applications in renewable energy conversion, including fuel cells and photocatalysis. The plant-mediated synthesis method reduces toxicity concerns, making these nanoparticles safer for biomedical and therapeutic applications.
[0098] It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.
, Claims:CLAIMS:
I / We Claim:
1. A method for synthesizing bimetallic gold-palladium nanoparticles (ScF Au-PdNPs), comprising:
boiling a fruit paste in water using a bain- marie method, followed by filtration for preparing an aqueous fruit extract of sarcolobus carinatus;
mixing the aqueous fruit extract of Sarcolobus carinatus with an aqueous solution at a 1:6 ratio to obtain a nanoparticles mixture, wherein the aqueous solution comprises a combination of 1mM chloroauric acid (HAuCl₄.3H₂O) and 2mM palladium chloride (PdCl₂) in a ratio of 1:2; and
incubating the mixture at room temperature for a required time period to form bimetallic nanoparticles (Au-PdNPs).
2. The method as claimed in claim 1, wherein the bimetallic nanoparticles comprise a palladium core and a gold shell, upon the synthesis of the bimetallic nanoparticles using HAuCl₄·3H₂O and PdCl₂ in the ratio of 1:2.
3. The method as claimed in claim 1, wherein the nanoparticles mixture of the aqueous fruit extract with the aqueous solution of 1 mM HAuCl₄.3H₂O and 2 mM PdCl₂ is incubated at a room temperature for a time period of at least 15 min to obtain the bimetallic nanoparticles.
4. The method as claimed in claim 1, wherein the synthesized bimetallic nanoparticles exhibit a surface plasmon resonance peak at 532 nm.
5. The method as claimed in claim 1, wherein the bimetallic nanoparticles are synthesized at pH 4-12 and remain stable for at least 37 days at room temperature and 4°C.