Nanocomposite System Research Articles

AIBI Modified Mesoporous Copper Sulfide Nanocomposites for Efficient Non-Oxygen Dependent Free Radicals-Assisted Photothermal Therapy in Uveal Melanoma.

Uveal melanoma (UM) is an ocular cancer predominantly affecting adults, characterized by challenging diagnostic outcomes. This research endeavors to develop an innovative multifunctional nanocomposite system sensitive to near-infrared (NIR) radiation, serving as both a non-oxygen free-radical generator and a photothermal agent. The designed system combines azobis isobutyl imidazoline hydrochloride (AIBI) with mesoporous copper sulfide (MCuS) nanoparticles. MCuS harnesses NIR laser energy to induce photothermal therapy, converting light energy into heat to destroy cancer cells. Simultaneously, AIBI is activated by the NIR laser to produce alkyl radicals, which induce DNA damage in remaining cancer cells. This distinctive feature equips the designed system to selectively eliminate cancers in the hypoxic tumor microenvironment. MCuS is also beneficial to scavenge the overexpressed glutathione (GSH) in the tumor microenvironment. GSH generally consumes free radicals and hiders the PDT effect. To enhance control over AIBI release in cancer cells, 1-tetradecyl alcohol (TD), a phase-changing material, is introduced onto the surface of MCuS nanoparticles to create the final AMPT nanoparticle system. In vitro and in vivo experiments confirm the remarkable anti-tumor efficacy of AMPT. Notably, the study introduces an orthotopic tumor model for UM, demonstrating the feasibility of precise and effective targeted treatment within the ocular system.

Kaolin supported synergistic effects in g-C3N4/V2O5 nanocomposite systems for advanced energy storage applications

In order to investigate the synergistic potential of a new nanocomposite for improved energy storage applications, this work combines graphitic carbon nitride (g-C3N4), vanadium pentoxide (V2O5) and kaolin. Kaolin functions as a structural matrix, offering stability and support for the integration of g-C3N4 and V2O5 nanoparticles. It is well-known for its wide availability and thermal characteristics. A variety of analytical methods, such as electrochemical analysis, scanning electron microscopy and X-ray diffraction, are used to characterise the synthesised nanocomposite. The specific capacitance and cycling stability of the nanocomposite's electrochemical performance are rigorously assessed. Key issues in efficiency, stability and cost-effectiveness are addressed by an optimised material for advanced energy storage systems, which is the result of the synergistic effects coming from the unique features of each component. With a superior cyclic stability and capacitance retention of 77.7 % even after 2000 cycles, the composite material exhibits a higher specific capacitance value of 415 Fg−1 at 5 mVs−1. This work is a major step towards the creation of novel nanocomposites for high-performing, environmentally friendly energy storage systems.

Unleashing the potential: Multifunctionality of PVDF-HFP based ternary nanocomposite films - magnetoelectric, energy harvesting and impact sensing performance

Multifunctional materials are proving to be highly promising for advancing various technologies, including magneto-mechano-electric energy harvesting devices and flexible sensors. This study focused on synthesizing a polyvinylidene fluoride-hexafluoropropylene-metal-oxide-layered silicate nanocomposite system using a cost-effective solution casting technique. The performance of the system was evaluated in terms of magnetoelectric behaviour, energy harvesting capabilities, and impact sensing. The nanocomposite films demonstrated a peak-to-peak voltage of 12.2 V with a filler loading of 15 wt% and an applied force of 9 N, along with a magnetoelectric coupling coefficient of 20.6 mVcm−1Oe−1. The device's ability to scavenge biomechanical energy during body movements like foot stamping, arm bending, finger flexing, and wrist bending was successfully verified. Furthermore, rigorous durability testing was conducted through repeated energy harvesting studies, proving the device's practicality and resilience. Notably, the developed device powered up six LEDs and a digital clock, while the impact sensor exhibited a linear relationship between output voltage and impact force. These findings highlight the remarkable potential of the polyvinylidene fluoride-hexafluoropropylene-metal-oxide-layered silicate nanocomposite system for multifunctional applications in various technological fields.

Enhancing capacitive performance of magnetite-reduced graphene oxide nanocomposites through magnetic field-assisted ion migration.

The transition towards renewable energy sources necessitates efficient energy storage systems to meet growing demands. Electrochemical capacitors, particularly electric double-layer capacitors (EDLCs), show promising performance due to their superior properties. However, the presence of resistance limits their performance. This study explores using an external magnetic field to mitigate ion transfer resistance and enhance capacitance in magnetite-reduced graphene oxide (M-rGO) nanocomposites. M-rGO nanocomposites with varying weight ratios of magnetite were synthesized and comprehensively characterized. Characterization highlighted the difference in certain parameters such as C/O ratio, the Id/Ig ratio, surface area and particle size that contribute towards alteration of M-rGO's capacitive behaviour. Electrochemical studies demonstrated that applying a magnetic field increased specific capacitance by approximately 20% and reduced resistance by 33%. Notably, a maximum specific capacitance of 16.36 F/g (at a scan rate of 0.1 V/s) and 27.24 F/g (at a current density of 0.25 A/g) was achieved. These improvements were attributed to enhanced ion transportation and migration at the electrode/electrolyte interface, lowering overall resistance. However, it was also observed that the aforementioned parameters can also limit the M-rGO's performance, resulting in saturated capacitive state despite a reduced resistance. The integration of magnetic fields enhances energy storage in nanocomposite systems, necessitating further investigation into underlying mechanisms and practical applications.

Photoresponse, thermal and electrical behaviors of MXene-based polysulfone nanocomposite

The Ti3C2Tx MXene nanosheet was prepared by 40% (v/v) hydrofluoric acid etching at 20 °C for 48 h and delamination of bulk MAX Ti3AlC2 precursor material. A 2D nanomaterial MXene Ti3C2Tx as a nanofiller was introduced to polysulfone (PSulfone) matrix. MXene and PSulfone/MXene nanocomposite systems were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope, Fourier-transform infrared and thermogravimetric analysis instruments. Dielectric and electrical characterization of PSulfone/MXene nanocomposite was carried out. The electrical resistance of Ti3C2Tx MXene from measurement current (I)–voltage (V) was measured as 116 Ω. Pure PSulfone matrix exhibits typical insulator behavior, and MXene exhibits a good conductor behavior. But, when MXene was added to the pure PSulfone matrix, the resistance of the MXene/PSulfone nanocomposite increased moderately compared to that of pure MXene. In spite of the excess of surface functional groups, MXene showed surprisingly good electron transport across the surface, while in the case of PSulfone/MXene nanocomposite, the insulating behavior of PSulfone significantly reduced the electron transport of MXene. The semiconductor behavior of PSulfone/Ti3C2Tx MXene nanocomposite indicates that MXene provides efficient charge carrier transfer in the nanocomposite system. By comparing the TGA results between the PSulfone and different weight ratios of PSulfone/Ti3C2Tx MXene nanocomposites, it was determined that MXene nanosheets had a significant effect in slightly accelerating the thermal degradation of PSulfone. Optical conductivity was investigated by preparing a film of PSulfone/MXene nanocomposite on an interdigital contact. It was observed that the optical current values changed depending on the increasing illumination intensity. Considering current–voltage measurements, the photocurrent generation potential of PSulfone/MXene nanocomposite shows that it can be used in photodevice production.

Preparation and characterization of high density polyethylene with TiO2 modified PEG 6000 filler as a landfill liner material

High-density polyethylene is an engineering polymer that is used in bottom liners of landfills. However, to be used in the environment application, it needs to have good mechanical and thermal qualities. Incorporation of inorganic fillers such as titanium dioxide into a polymer aimed at enhancing several features such as mechanical strength, thermal stability, and resistance to surface wear. In this study, HDPE preparation was carried out by adding TiO2 nanoparticles. TiO2 nanoparticles were synthesized using the precursor TiCL4 and then modified with the addition of PEG 6000. Furthermore, the resulting TiO2 was used as a filler in thermoplastic HDPE. Characterization of high-density polyethylene with TiO2 filler as a landfill liner material shows an increase in mechanical and thermal properties. The HDPE sample containing 8%wt filler had the highest tensile strength, measuring at 84.72 Mpa. In contrast, the use of 6wt% filler resulted in the lowest recorded tensile strength, measuring at 56.24 Mpa. The elastic modulus had its highest increase at 8 wt% TiO2, reaching a value of 729.33 MPa. However, the addition of 6 wt% TiO2 resulted in a notable decrease in elastic modulus, with a value of 522.79 MPa. Additionally, it was observed that the highest elongation at break was achieved with a 4% weight filler, resulting in a value of 49.37%. Similar to the reduction observed in the elastic modulus value, the elongation at break exhibited a substantial decrease of 39.22% upon the addition of 6wt% TiO2. DSC scan curves for both the fabricated nanocomposite systems clearly show that they are affected by the nanofiller and its percentage fraction. There was an increase in Tm1 in the composition of 8wt% TiO2, while an increase in Tm2 occurred in 2wt% TiO2. Therefore, HDPE which is given TiO2 filler has the potential to be used as landfill liner material.

Gold nanoparticles doped organic liquid crystalline material for fast charge migration in nano-devices

ABSTRACT With the ever-growing need for low-cost, easily processable multifunctional materials and increasing miniaturisation in devices, we have landed in the era of nanodevices. Discotic liquid crystals are multifaceted materials that have shown their applicability as photonic devices, nanowires, optical switches, memory storage devices and many more. These materials show 1D conductivity which can be boosted upon doping with a suitable doping agent in appropriate concentrations. In this work, we present nanocomposite materials composed of a triphenylene discotic liquid crystal material, doped with thiol capped gold nanoparticles, and propose to apply it as a charge transportation layer in nanodevices for faster charge migration. Various techniques have been used to analyse the effect of doping on the different electrical, optical and lattice parameters of these nanocomposite systems. An increase in the value of the conductivity is obtained at higher temperatures, and it is successfully preserved till room temperature due to the presence of thiol capped gold nanoparticles in the columnar matrix. Thus, an increase in conductivity, lowering of the optical band gap, broadening of UV-Visible absorbance peak and decrease in core-to-core distance infers the increase in stability and optical and conduction properties of the host material after doping.

Studies on the structural and magnetic properties of PMMA/Ni nanocomposite system prepared by embedding Ni nanoparticles in the PMMA films

PMMA/Ni nanocomposite films have been prepared by embedding Ni nanoparticles and maintaining their different thickness (5–50 nm) in PMMA (polymethylmethacrylate) film matrix by using ion beam sputtering (IBS) technique. Grazing incidence x-ray diffraction (GIXRD) results reveal Ni is present in metallic form in the FCC phase. X-ray reflectivity (XRR) is used to measure the nominal thickness of the Ni nanoparticle layer. Surface morphology was studied using atomic force microscopes (AFM). SXAS (soft x-ray absorption spectroscopy) studies on PMMA/Ni nanocomposites were done using synchrotron radiation to understand the electronic structure of these films which reveals that Ni is present in metallic state confirming that PMMA as host matrix protects the magnetic Ni nanoparticles from external oxidation. The magneto-optical Kerr effect (MOKE) magnetometer and MOKE microscope were employed to study the magnetic properties and simultaneously record the real time evolution of magnetic domains at 0°, 45°, and 90° azimuthal angles. All films show soft ferromagnetic behaviour and all the films show isotropic behaviour except one with Ni nanoparticle layer thickness of 40 nm. MOKE micrographs witness the gradual growth of magnetic domains with increase in thickness of Ni nanoparticle layer. These PMMA/Ni nanocomposite films may be viewed as potential candidate for futuristic functional material.

Development of polysaccharide-coated layered double hydroxide nanocomposites for enhanced oral insulin delivery

Oral insulin (INS) is predicted to have the most therapeutic advantages in treating diabetes to repress hepatic glucose production through its potential to mimic the endogenous insulin pathway. Many oral insulin delivery systems have been investigated. Layered double hydroxide (LDH) as an inorganic material has been widely used in drug delivery thanks to its appealing features such as good biocompatibility, low toxicity, and excellent loading capability. However, when used in oral drug delivery, the effectiveness of LDH is limited due to the acidic degradation in the stomach. In this study, to overcome these challenges, chitosan (Chi) and alginate (Alg) dual-coated LDH nanocomposites with the loading of insulin (Alg-Chi-LDH@INS) were developed by the layered-by-layered method for oral insulin delivery with dynamic size of ~ 350.8 nm, negative charge of ~ − 13.0 mV, and dispersity index 0.228. The insulin release profile was evaluated by ultraviolet–visible spectroscopy. The drug release profiles evidenced that alginate and chitosan coating partially protect insulin release from a burst release in acidic conditions. The analysis using flow cytometry showed that chitosan coating significantly enhanced the uptake of LDH@INS by Caco-2 cells compared to unmodified LDH and free insulin. Further in the in vivo study in streptozocin-induced diabetic mice, a significant hypoglycemic effect was maintained following oral administration with great biocompatibility (~ 50% blood glucose level reduction at 4 h). This research has thus provided a potential nanocomposite system for oral delivery of insulin.Graphical

Milled graphitic nanoparticle toughened epoxy composites via increased resistance to in-plane crack propagation

Fascinating features of 2D-based carbon materials like graphene have drawn increasing attention to fulfill the desire to enhance the fracture toughness of epoxy composites. However, challenges remain to improve their dispersibility in polymers and increase interaction ability. Thus, work is needed to synthesize alternative cost-effective 2D carbon nanofillers capable of delivering consistent performance as a reinforcer to monitor the fracture toughness of the epoxy composites. The present study demonstrates transforming graphite to ball-milled graphite (BMG) via an effective high-energy wet ball milling process. Herein a noteworthy size reduction is achieved for the BMG ranging from ∼217 to 227 nm. Microscopic investigation spotted an exfoliated 3D networked graphite nanosheet with nanopores. These BMGs were functionalized to attach amine-based silane moieties and were incorporated into the epoxy network. Consequently, even at higher loading levels, they showed their astonishing capability to enhance the crack far field resistance of nanocomposite resulting in significantly improved fracture toughness and energy to ∼2.31 MPa m1/2 and ∼11.30 kJ/m2, respectively. Improvement is ascribed to the better dispersing ability of BMG, which provides a consistent strong interfacial interaction with the epoxy network to modulate material resistance to fracture. Such environmentally friendly nanofillers must be industrially acceptable for synthesizing durable epoxy nanocomposite systems and can be utilized to prepare structural composites.

Near-infrared light-activatable, analgesic nanocomposite delivery system for comprehensive therapy of diabetic wounds in rats

Impaired angiogenesis, bacterial infection, persistent severe pain, exacerbated inflammation, and oxidative stress injury are intractable problems in the treatment of chronic diabetic ulcer wounds. A strategy that effectively targets all these issues has proven challenging. Herein, an in-situ sprayable nanoparticle-gel composite comprising platinum clusters (Pt) loaded-mesoporous polydopamine (MPDA) nanoparticle and QX-314-loaded fibrin gel (Pt@MPDA/QX314@Fibrin) was developed for diabetic wound analgesia and therapy. The composite shows good local analgesic effect of QX-314 mediated by near-infrared light (NIR) activation of transient receptor potential vanilloid 1 (TRPV1) channel, as well as multifunctional therapeutic effects of rapid hemostasis, anti-inflammation, antioxidation, and antibacterial properties that benefit the fast-healing of diabetic wounds. Furthermore, it demonstrates that the composite, with good biodegradability and biosafety, significantly relieved wound pain by inhibiting the expression of c-Fos in the dorsal root ganglion and the activation of glial cells in the spinal cord dorsal horn. Consequently, our designed sprayable Pt@MPDA/QX314@Fibrin composite with good biocompatibility, NIR activation of TRPV1 channel-mediated QX-314 local wound analgesia and comprehensive treatments, is promising for chronic diabetic wound therapy.

Polyoxometalate-HKUST-1 composite derived nanostructured Na-Cu-Mo2C catalyst for efficient reverse water gas shift reaction.

Transforming CO2 to CO via reverse water-gas shift (RWGS) reaction is widely regarded as a promising technique for improving the efficiency and economics of CO2 utilization processes. Moreover, it is also considered as a pathway towards e-fuels. Cu-oxide catalysts are widely explored for low-temperature RWGS reactions; nevertheless, they tend to deactivate significantly under applied reaction conditions due to the agglomeration of copper particles at elevated temperatures. Herein, we have synthesized homogeneously distributed Cu metallic nanoparticles supported on Mo2C for the RWGS reaction by a unique approach of in situ carburization of metal-organic frameworks (MOFs) using a Cu-based MOF i.e. HKUST-1 encapsulating molybdenum-based polyoxometalates. The newly derived Na-Cu-Mo2C nanocomposite catalyst system exhibits excellent catalytic performance with a CO production rate of 3230.0 mmol gcat-1 h-1 with 100% CO selectivity. Even after 250 h of a stability test, the catalyst remained active with more than 80% of its initial activity.

A novel nanocomposite drug delivery system for SARS-CoV-2 infections

To develop an inhalable drug delivery system, we synthesized Remdesivir-loaded nanocomposites (RDV NCs) by coating drug-loaded nanoparticles with supramolecular cell-penetrating peptide nanofibers, enhancing uptake and intracellular drug delivery.

Ternary low-temperature phototherapy nano-systems for the treatment of diabetic wounds.

The physicochemical environment at the sites of chronic diabetic wounds is an ideal habitat for bacteria, which exacerbate the deterioration of the microenvironment at the wound sites and consequently delay wound healing. In recent years, photothermal therapy has been considered an ideal non-antibiotic antimicrobial strategy. However, photothermal therapy alone is prone to cause damage to the body tissues. Herein, a (zeolitic imidazolate framework-8) ZIF-8/(mesoporous polydopamine) MPDA@(deoxyribonuclease I) DNase I ternary nanocomposite system was constructed, which exhibited good antimicrobial and antioxidant properties. Specifically, DNase I was first encapsulated into MPDA nanoparticles (NPs) and then coated with ZIF-8, which rapidly degrades in an acidic bacterial environment, triggering the release of antimicrobial Zn2+ and DNase I, thus enabling low-temperature (∼45 °C) PTT antimicrobial therapy. Meanwhile, the NPs can effectively regulate the oxidative stress environment at the trauma site because of the antioxidant effect of MPDA. Moreover, the experimental results of the diabetic wound infection mouse model showed that the prepared NPs could kill bacteria well and accelerate wound healing. Overall, the phototherapy strategy proposed in this study shows great potential in the treatment of chronically infected wounds.

Electrospun nanofibers combined with Fe-doped mesoporous bioactive glass nanoparticles induce in vitro melanoma cell death

Iron (Fe) doped-mesoporous bioactive glasses are among the most promising candidates in cancer therapy; the present study reports the successful fabrication and characterization of a series of anticancer and pro-regenerative nanocomposites of polycaprolactone and gelatin nanofibers combined with Fe-doped mesoporous bioactive glasses. The anticancer potential and regenerative capacity of the prepared nanocomposite were studied on melanoma (A375 cell line) and normal fibroblast cells (L929 cell line) by using the MTT assay, annexin V/PI apoptosis assay, intracellular reactive oxygen species (ROS) generation, malondialdehyde assay, as well as adhesion and migration assessments. The characterization of the nanofibers containing 20 % (wt.%) glass particles revealed a suitable tensile strength (5.8 MPa), controlled swelling (355.5 % after 24 hours), and degradability (31.33 % after 28 days). The viability of A375 cells was significantly reduced (up to 77 %) after treatment with the 20 % glass-impregnated nanofibers along with 58 % and 8 % increase in their apoptosis and necrosis, respectively. Interestingly, this nanocomposite showed no significant adverse effects on normal fibroblasts. In conclusion, this study suggests the possibility of the bioactive glass nanoparticles/electrospun nanofiber composites in the treatment of cancers (e.g., melanoma) as well as in providing a suitable microenvironment for tissue repair and regeneration. However, performing in vivo studies is required to provide clear evidence of the anticancer potential of this nanocomposite system.

Enhancing supercapacitor performance of Ni-Co-Mn metal-organic frameworks by compositing it with polyaniline and reduced graphene oxide.

Metal-organic frameworks (MOFs) are one of the most sought-after materials in the domain of supercapacitors and can be tailored to accommodate diverse compositions, making them amenable to facile functionalization. However, their intrinsic specific capacitance as well as energy density is minimal, which hinders their usage for advanced energy storage applications. Therefore, herein, we have prepared six electrodes, i.e., Ni-Co-Mn MOFs, polyaniline (PANI), and reduced graphene oxide (rGO) along with their novel nanocomposites, i.e., C1, C2, and C3, comprising MOFs : PANI : rGO in a mass ratio of 100 : 1 : 0.5, 100 : 1 : 1, and 100 : 1 : 10, respectively. The polyaniline conducting polymer and rGO enabled efficient electron transport, enhanced charge storage processes, substantial surface area facilitating higher loading of active materials, promoting electrochemical reactions, and ultimately enhanced nanocomposite system performance. As a result, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques confirmed the successful synthesis and revealed distinct morphological features of the materials. Following electrochemical testing, it was observed that composition C2 exhibited the highest performance, demonstrating a groundbreaking specific capacitance of 1007 F g-1 at 1 A g-1. The device showed a good energy density of 25.11 W h kg-1 and a power density of 860 W kg-1. Remarkably, the device demonstrated a capacity retention of 115% after 1500 cycles, which is a clear indication of the wettability factor, according to the literature. The power law indicated b-values in a range of 0.58-0.64, verifying the hybrid-type behavior of supercapacitors.

Physico-chemical properties of nanocomposites based on multi-component hybrid quantum dots

Composites of inorganic nano-objects such as quantum dots (QDs) and organic materials such as luminescent or polymers can be developed based on them for special applications such as optical devices, electro-optical devices and computing. In the study, nanocomposites based on multi-component quantum dots were obtained and nanocomposites were obtained by inserting them into polymethyl methacrylate (PMMA). First, core-shell hybrid quantum dots were synthesized, then core/shell/shell systems were obtained, and their absorption, luminescence spectra and sizes were obtained. In this work, information is presented about the opening of wide opportunities for the use of semiconductor nanocrystals related to obtaining new hybrid nanocomposite systems for nanomedicine and biomedicine.

Metal Filled Nanostructured Silicon a Platform to Interlink Magnetism and Optics

This presentation deals with the utilization of nanostructured silicon (porous silicon and silicon nanotubes) for deposition of various metals, especially magnetic ones, within the pores/tubes. The novel magnetic properties of the semiconducting/magnetic composites which arise due to the nanoscopic size of the used materials are investigated with respect to optical and magnetic on-chip applications.Porous silicon is fabricated by anodization of a silicon wafer in an aqueous hydrofluoric solution. The morphology of the porous structures depends on the doping density of the used wafer and on the applied current density as well as the electrolyte concentration. The ferromagnetic metals are deposited within the porous structures electrochemically in using the corresponding metal salt solution as electrolyte. A modification of the electrochemical parameters results in adjustable size and shape of the deposits. Ni and Co, both metals are electrodeposited within the nanostructured silicon in using aqueous NiSO4 and CoSO4 solutions by applying a current density between 10 and 20 mA/cm2 and a frequency between 0.05 and 0.2 Hz.One of our key topics is luminescent porous silicon loaded with magnetic metals to enhance the photoluminescence, with the final aim to influence/control the optical properties by a magnetic field. The metal deposits affect the optical properties but also give rise to specific magnetic behavior (1). Due to the metal filling of the porous silicon the photoluminescence is blue-shifted and furthermore an increase of the intensity is observed. The influence of the magnetic metal filling on the optical properties (photoluminescence, decay time) is discussed, and the magnetic characterization of the nanocomposites is presented.A further issue, the deposition of hard and soft magnetic materials within the nanostructures, aiming in the fabrication of arrays of permanent nanomagnets is presented (2). Here the investigation of the magnetic behavior of bi-metal nanostructures within nanostructured silicon with the aim to exploit the magnetic properties of both metals and gain control of the exchange coupling between the two metals especially with respect to their volume ratio is discussed. Furthermore, a variation of the structure size and the proximity of the metal deposits modify the exchange coupling and thus the energy product. Nanocomposite systems with an energy product as high as possible should be achieved to give rise to on-chip applications using permanent nanomagnets, especially arranged in arrays.(1) P. Granitzer, et al, Frontiers in Physics, 8 (2020) 121(2) K. Rumpf, et.al, Phys. Stat. Sol. A, 217 (2020) 1901040

Synthesis and Characterization of Responsive Antimicrobial Materials for Chronic Wound Management

Chronic wound treatment requires the ability to regulate the wound healing process and mitigate the propagation of bacterial infection with constant monitoring, in real-time. The need for multi-functional wound management materials has emerged as a significant research area with promise shown in the incorporation of antimicrobial agents within responsive polymeric materials to elicit signals providing dynamic information about the healing process. Traditional wound dressings provide a barrier between the outside environment and the wound; however, these methods are increasingly becoming less effective. Hydrogels synthesized from natural biopolymers have emerged due to their intrinsic properties such as biodegradability and non-cytotoxicity and enhanced from their well-defined, three-dimensional, non-covalent networks ideal for modification and functionalization to create “micro-reactors.” Previous work focused on the strategic design of an alginate-based hydrogel containing dual functional additives (i.e., amino acids) paired with photochemically prepared Ag- and Cu-TiO2 nanoparticles (Ag/Cu-NPs) to understand the synergistic interactions of the polymer chains, cross-linkers, and additives. The antimicrobial effectiveness of the composite was examined using an epi-fluorescent optical tweezer to measure the rates of bacterial cell death. Results showed that with the incorporation of the NPs there is a decrease in green signal (live cells) within 1 hour of exposure. Furthermore, the healing rates of simulated wounds using human dermal fibroblasts were explored along with changes in the expression of growth factors that promote wound healing, such as collagen and TGF-b. This work focuses on a two-layer responsive material with a wound-healing layer and a conductive layer formed through the secondary functionalization of the composite system through a metal-coordination-assisted photopolymerization of conductive polymers (i.e. aniline). Preliminary results show there is uniform polymeric chain growth seen in enhanced charge transfer through the matrix upon an applied voltage. Studies have also been conducted to measure the impact of saturation of the bandage through simulated wound exudate that revealed once saturation occurs, the passing of electricity between the ions found in wound exudate carried current through the composite, increasing the conductivity, leading to the signaling of an LED prompting replacement. The resulting two-layer nanocomposite system then functions as a responsive, antimicrobial wound healing material capable of eliminating constant monitoring with application in healthcare and home settings.

Cellulose Based Antimicrobial Nanocomposite Surface Coatings for Sensing of Biological Contaminants

Biomimetic nanocomposite systems have emerged as polymeric scaffolds that utilize cooperative relationships to enhance physiochemical properties for the next generation of biosensors. These composite systems can be synthesized from biopolymers such as cellulose to manipulate the highly ordered, three-dimensional network and natural properties to create a tunable pore structure for “micro-reactor” functionality. Thus, it is vital to understand the fundamental mechanistic interactions between the biopolymer system and the functional additives incorporated within the matrix. This work focuses on designing and characterizing a conductive biopolymeric coating for the detection or electrochemical sensing of biological contaminants present on high-touch surfaces. Specifically, cellulose base polymers infused with photochemically prepared antimicrobial metal nanoparticles (MNP’s) and functional additives will be employed as the scaffold coupled with secondary functionalization via metal-coordination assisted photopolymerization of conductive polymers (i.e., aniline, pyrrole). Initial results of the antimicrobial effectiveness of the polymeric base network using an epi-fluorescent optical tweezer show an increased rate of bacterial cell death with the inclusion of MNP’s exhibited through a decrease in the green signal (live cells). Upon secondary functionalization of these composites, studies have shown uniform polymeric chain growth evident by enhanced charge transfer, 30-50 milliamps, through the matrix upon an applied voltage of 5 volts. Unraveling the adsorption/desorption phenomena between the “high touch” surfaces and the carrier media is essential. Initial results show that this correlation between adsorption/desorption rates and surface texturing (surface energy and roughness) can provide insight into the adhesion force threshold. Furthermore, the kinetic results served as a foundation for advancing an electrically active antimicrobial nanocomposite biopolymer coating with a tunable surface topography to exhibit site-specific responsivity in the presence of a biological contaminant. Results show that upon adhesion of a biological contaminant (specifically mucin), there is an impedance change caused by the increased resistance from the adherent which disrupted the resting potential and decreased the current output at the adsorption site. However, the contaminant was removed upon an applied voltage, and the potential returned to an equilibrated state.