Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.

Introduction to Spectroscopy

Natural and synthetic polymers for wounds and burns dressing

Advanced Therapeutic Dressings for Effective Wound Healing—A Review

The scientific community is focused on the development of inexpensive and high-performing membrane materials for proton exchange membrane (PEM) fuel cells (FCs). The major approach to reducing the cost of FCs, which is crucial for the widespread acceptance of FCs as energy sources for various practical applications, is reducing the cost of the membrane. Efforts are being made in the development of advanced polymeric materials, which will satisfy the technical and economic demands of the consumers. Because most alternative membranes are outperformed by Nafion membranes over an entire set of important properties, it may be worthwhile to compromise on certain parameters to develop alternative specialized membranes. This review presents the properties (mainly conductivity and chemical and mechanical stability) of modern solid polymer electrolytes (SPEs) for PEM FCs.

Review of Advanced Materials for Proton Exchange Membrane Fuel Cells

Natural hydrogels are promising scaffolds to engineer epidermis. Currently, natural hydrogels used to support epidermal regeneration are mainly collagen- or gelatin-based, which mimic the natural dermal extracellular matrix but often suffer from insufficient and uncontrollable mechanical and degradation properties. In this study, a photocrosslinkable gelatin (i.e., gelatin methacrylamide (GelMA)) with tunable mechanical, degradation, and biological properties is used to engineer the epidermis for skin tissue engineering applications. The results reveal that the mechanical and degradation properties of the developed hydrogels can be readily modified by varying the hydrogel concentration, with elastic and compressive moduli tuned from a few kPa to a few hundred kPa, and the degradation times varied from a few days to several months. Additionally, hydrogels of all concentrations displayed excellent cell viability (>90%) with increasing cell adhesion and proliferation corresponding to increases in hydrogel concentrations. Furthermore, the hydrogels are found to support keratinocyte growth, differentiation, and stratification into a reconstructed multilayered epidermis with adequate barrier functions. The robust and tunable properties of GelMA hydrogels suggest that the keratinocyte laden hydrogels can be used as epidermal substitutes, wound dressings, or substrates to construct various in vitro skin models.

/pdf/photocrosslinkable-gelatin-hydrogel-for-epidermal-tissue-5g7705zk2k.pdf

Photocrosslinkable Gelatin Hydrogel for Epidermal Tissue Engineering.

The purpose of the present study was to develop and design pectin and polyvinyl pyrrolidone (PVP) blended hydrogel membranes (PEVP), with different pectin: PVP ratios (1:0.2, 1:0.4, 1:0.6, 1:0.8 and 1:1 w/w), which were prepared by using a conventional solution casting technique. An attempt has been made to characterize the hydrogel membranes by various instrumental techniques like, FTIR (Fourier transform infrared) spectroscopy, X-ray diffraction (XRD), Differential scanning calorimetry (DSC), tensile strength test and scanning electron microscopy (SEM). The release patterns of the drug (salicylic acid) from the hydrogel membrane were done in three different release mediums (pH 1.4, pH 7.4 and distilled water) and samples were analyzed spectrophotometrically at 294 nm wavelength on a UV Vis spectrophotometer. MTT assay was done to ensure cytocompatibility of the pectin/PVP hydrogel membranes using B16 melanoma cells. FTIR spectroscopy indicated the presence of secondary amide (I) absorption bands. The XRD study shows decrease in crystallinity of the hydrogel membranes with increase in PVP ratio. DSC study shows an increase in Tg of pectin after blending with PVP. It was found that tensile strength increases with increasing PVP ratios in the hydrogel membranes. The prepared hydrogel membranes were found to be biocompatible with B16 melanoma cells.

/pdf/synthesis-and-characterization-of-pectin-pvp-hydrogel-34wyyr8rpp.pdf

Synthesis and Characterization of Pectin/PVP Hydrogel Membranes for Drug Delivery System

In the present study an attempt was made to graft polyacrylamide on pectin. The grafted polymer was characterized by FTIR spectroscopy, differential scanning calorimetry and X-ray diffraction. Rheological property of pectin solution was compared with the product solution. The grafted polymer was cross-linked with varying amount of glutaraldehyde. The swelling properties of the cross-linked product were also studied. The salicylic acid, an antipyretic drug, was incorporated in the cross-linked gel as a model drug and the drug release studies were done in a modified Franz's diffusion cell. The effect of cross-linking density on the release property of salicylic acid was studied through the cross-linked product. The product showed better film forming property and gelling property than pectin. The comparative rheological properties of pectin and grafted copolymer indicated change in the property of the product. FTIR studies indicated incorporation of amide group. Differential scanning calorimetry and XRD suggested formation of a new polymer. Swelling study indicated pH dependent swelling of the cross-linked hydrogel. Salicylic acid release indicated pH dependent release from the hydrogel.

Development of pH sensitive polyacrylamide grafted pectin hydrogel for controlled drug delivery system.

Pectin is known as a miracle polymer of natural origin because of its excellent biodegradable and biocompatible nature. Pectin is commercially extracted from different citrus products like apple, pomace, and oranges under mildly acidic conditions. Pectin has been mainly divided in to major group’s namely high methoxyl pectin and low methoxyl pectin. Pectin is a high value functional food ingredient which is widely used as a gelling agent and stabilizer in food industries. Pectin has been widely investigated for targeted drug delivery and other potential biomedical applications. Pectin is known to be rapidly degraded by colonic microorganisms and thus makes it a potential carrier for colon targeted drug delivery. Pectin based formulations have shown tremendous promise as novel biomaterials for development of implantable and prosthetic devices. This paper reviews the recent research progress in development of pectin based formulations (polymer hydrogels, films, tablets, microspheres, nanoparticles and scaffolds) and their biomedical applications.

Pectin based formulations for biomedical applications: a review

Chitosan coated alginate-xanthan gum bead enhanced pH and thermotolerance of Lactobacillus plantarum LAB12.

The present work deals with the development of pectin-gelatin (PEGE) hydrogel membranes for wound dressing applications. The prepared hydrogels were characterized by FTIR spectroscopy, XRD spectroscopy, water vapor transmission rate (WVTR) test and tensile strength test. Morphology and thermal stability of the membranes were analyzed by Field emission scanning electron microscopy (FESEM) and thermogravimetric analysis (TGA). The swelling studies of the hydrogels were conducted in different pH buffer solutions (pH 1.4, 5.4, 7.4 and 9.4). FTIR spectra of the hydrogels indicated considerable lowering in usual –OH stretching vibration peak of pectin and gelatin, which suggests the development of probable intermolecular interactions between the two natural polymers. XRD study revealed the decrease in crystallinity of hydrogels as compared to parent pectin. The morphological analysis of the hydrogel revealed highly interconnected honeycomb type architecture with pore size ranging from 10 to 40 μm. It was found that increase in gelatin ratio significantly improves the porous nature of the membranes. TGA study showed the enhanced thermal stability of PEGE hydrogel as compared to reference pectin. Tensile strength (TS) and elongation at break (EB) was found to increase with gelatin content in the hydrogel membranes but further increase leads to decrease in TS and EB. The WVTR analysis of the membranes showed the moisture retentive properties indicating its possible use in moist wound care. The PEGE hydrogels were found to be cytocompatible with B16 melanoma cells.

Rakesh Kumar Mishra

Papers

Synthesis and Characterization of Pectin/PVP Hydrogel Membranes for Drug Delivery System

Development of pH sensitive polyacrylamide grafted pectin hydrogel for controlled drug delivery system.

Pectin based formulations for biomedical applications: a review

Chitosan coated alginate-xanthan gum bead enhanced pH and thermotolerance of Lactobacillus plantarum LAB12.

Development and characterization of pectin/gelatin hydrogel membranes for wound dressing