Effect of cross-linkers in fabrication of carrageenan-alginate matrices for tissue engineering application.

The three-dimensional (3D) scaffold serves as a structural substrate and as a niche for cell proliferation to ensure tissue regeneration. Ideal scaffolds should have porous structures with high pore interconnectivity to allow cell adherence, differentiation, and proliferation while ensuring suitable mechanical strength and biodegradability without inflicting any immune response. Cross-linker is one of the major factors that affect the mechanical and biological properties of scaffolds. In this study, different chemical cross-linker effects on scaffold architecture were examined. Porous 3D scaffolds based on carrageenan and alginate (CA) were successfully fabricated by a freeze-drying technique and using various cross-linkers like glutaraldehyde (GA), genipin, and ethyl (dimethylamino propyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS). The chemical cross-linker effects on the CA scaffold were characterized by scanning electron microscopy, differential scanning calorimetry, and thermogravimetry. A human fibroblast cell line (L929) was seeded into the fabricated scaffold, and cell proliferation was assessed by MTT and live/dead assay. Overall results suggested the potential cross-linkers for ideal CA biomaterial could be EDC/NHS among other agents tested as the scaffold CAEN was found to be porous, interconnected, and physically and mechanically stable. When compared to matrices with other cross-linkers, higher cell attachment, better cellular response, and higher metabolic activity could be observed in the scaffold synthesized using EDC/NHS as cross-linker.

Biofouling in Membrane Bioreactors: Mechanism, Interactions and Possible Mitigation Using Biosurfactants.

Biofouling roots damage to membrane bioreactors (MBRs), such as physical, functional and organisational changes and even therefore clogging of the membrane pores and successive microbial degradation. Further, it blocks the pores, results into a biomass cake and in due course reduces the membrane flux and leads to an increase in the operational costs. MBR fouling contributed to the rise in transmembrane pressure (TMP) and decrease in permeate flux (in case of constant pressure operation mode). Chemical surfactants adopted for the cleaning of membrane surfaces have certain disadvantages such as toxicity manifestations, damage to the membranes and high CMC concentrations. Biosurfactant surfactants have attained increasing interest due to their low toxicity, biodegradability, stability to extreme environmental conditions such as temperatures, pH and tolerance to salinity. The biosurfactants trapped the foulants via micelle formation, which distresses hydrophobic interactions amongst bacteria and the surface. Rhamnolipids as an anionic biosurfactant pose a significant interfacial potential and have affinity to bind organic matter. The present review discusses the problem of biofouling in MBRs, type and interactions of foulants involved and also highlights the mechanisms of biosurfactant cleaning, effect of different parameters, effect of concentration, TMP, flux recovery, permeability, mitigation practices and challenges.

Comparative Evaluation of Cotton PTFE Tape and Foam Pellets as Endodontic Spacer in Primary Teeth: An In Vivo Study.

Aim and objective: This study was conducted to microbiologically evaluate cotton, PTFE tape, and foam pellets as endodontic spacer in primary teeth. Materials and methods: Thirty primary second molars indicated for pulpectomy were included in this study. Followed by the completion of pulpectomy in each teeth cotton, PTFE tape, and foam pellets were placed as endodontic spacers randomly in 10 teeth each. The samples were collected from the pulp chamber at baseline and after 7 days to evaluate for microbial contamination of the same. The data obtained was tabulated and subjected to appropriate statistical analysis. Results: There was a statistically significant increase in the colony forming unit after 7 days in cotton and foam pellet group. But PTFE tape group showed very minimal contamination of the pulp chamber after 7 days. Conclusion: Within the limitations of this study, it can be concluded that PTFE tape found to be the best alternative to cotton as an endodontic spacer. Clinical significance: In case of multiple visit pulpectomy procedure, the state of sterility must be maintained in between the appointments until a definitive coronal restoration is placed following root-canal obturation. So it is mandatory to place an endodontic spacer under a provisional restoration to maintain the patency of the root canals and prevention of the microbial growth. The PTFE tape is inorganic, nonfibrous material which can be tightly packed without any voids under the provisional restoration. So PTFE tape is the best material to maintain the root canal patency and to provide a sterile environment by preventing the microbial growth under the provisional restoration as an endodontic spacer material in between the appointments. How to cite this article: Somani R, Arya MV, Singh DJ, et al. Comparative Evaluation of Cotton PTFE Tape and Foam Pellets as Endodontic Spacer in Primary Teeth: An In Vivo Study. Int J Clin Pediatr Dent 2022;15(1):74-78.

Preparation and clinical evaluation of succinylated collagen punctal plugs in dry eye syndrome: a pilot study.

AIM: This is a pilot study of 10 eyes of 6 patients. This paper describes the preparation and clinical evaluation of succinylated collagen punctal plugs (SCPP) in the treatment of dry eye syndrome (DES). METHODS: SCPP were prepared from succinylated collagen with the exact dimensions of the punctum (length 1.5-2.5 mm, diameter 0.2-0.5 mm, water content between 50 and 55%). All the patients were clinically evaluated for best corrected visual acuity (BCVA), tear fluid levels (TFL), protein content, tear fluid osmolarity (TFO), fluorescence staining of the cornea and tear break-up time (TBUT) before and after punctal occlusion with SCPP. RESULTS: TFL improved among all the patients after punctal occlusion with SCPP. BCVA showed improvement in case 4 (right eye/left eye), case 5 (left eye) and case 6 (right eye), who had developed dry eyes due to environmental conditions. Protein content increased on day 7 in all the patients and gradually decreased. TFO decreased on days 3 and 5 in all patients after punctal occlusion with SCPP, and showed the same levels on day 14. TFL, PC, TFO and TBUT showed significant improvement in all the patients after punctal occlusion with SCPP. CONCLUSION: All patients experienced symptomatic relief after punctal occlusion with SCPP. There was no discomfort, foreign body sensation, plug extrusion, corneal aberration, infection, or formation of pyogenic granuloma with SCPP. SCPP stands as a promising alternative to other punctal plugs in the treatment of DES.

Hermetic Seal in Obturation: An Achievable Goal with Recently Introduced Cpoint.

AIM AND OBJECTIVES: To evaluate and compare the dentinal microcrack formation after obturation using CPoint and gutta percha as root canal filling materials. MATERIALS AND METHODS: Forty orthodontically extracted single-rooted premolars were selected. The teeth were decoronated and were then divided into four groups (n = 10). In group I, samples were left unprepared and unfilled (negative control), in group II, samples were prepared and left unobturated (positive control), in group III, samples were prepared and obturation was done with Cpoint (F3) and endosequence bioceramic sealer, and in group IV, samples were prepared and obturation was done with Protaper gutta percha (F3) and endosequence bioceramic sealer. Then, the samples were kept for 1 week at 37°C and 100% humidity. All roots were then sectioned at 2 mm from the apex. Additional cross sections at a 4 mm level were made in groups III and IV. Then, the sections were observed under a scanning electron microscope and the presence of dentinal microcracks was checked. RESULTS: There was statistically nonsignificant difference for a mean number of microcracks in the samples after obturation with CPoint and gutta percha. CONCLUSION: CPoint can be used as an alternative to gutta percha as it provides better seal because of its lateral hygroscopic expansion without causing significant damage to the dentinal microstructure. CLINICAL SIGNIFICANCE: In spite of gutta percha being the gold standard in obturating material, still the desired hermetic seal could not be achieved. To achieve this attainable goal, a new material CPoint had been introduced, which has the ability to undergo hygroscopic expansion within the root canal. HOW TO CITE THIS ARTICLE: Somani R, Jaidka S, Singh DJ, et al. Hermetic Seal in Obturation: An Achievable Goal with Recently Introduced Cpoint. Int J Clin Pediatr Dent 2019;12(5):410-413.

Comparative Microbiological Evaluation after Caries Removal by Various Burs.

AIM: The aim of the study was to compare the caries removal efficacy in terms of bacteriology and efficiency in terms of time taken by conventional and smart burs. MATERIALS AND METHODS: A total of 40 extracted permanent molars with occlusal caries were selected for this study. These teeth were split at the center of carious lesion buccolingually, in order to obtain two similar halves. Thus, 80 samples were obtained in this way and were randomly divided into 2 groups of 40 samples each. Caries was removed using conventional burs in group I and polymer bur Smartprep (SS white) in group II. The time involved in caries removal was measured for both the groups. After excavation of all carious lesions, the samples were decalcified, dehydrated, and embedded in paraffin wax from which thin sections of 5 µm were obtained, which were histologically evaluated for bacterial presence under a light microscope. RESULTS: An intergroup comparison between conventional bur (group I) and smart bur (group II) showed a statistically nonsignificant difference in terms of the presence of microorganisms after caries removal with a p value of 0.073638 (p > 0.05). However, the time taken for caries removal was significantly more for smart burs than diamond burs with a p value of 0.001 (p < 0.05). CONCLUSION: The polymer burs were found to be as effective as the conventional burs in terms of microbial presence after caries removal, but are more time-consuming than conventional burs. HOW TO CITE THIS ARTICLE: Somani R, Chaudhary R, Jaidka S, et al. Comparative Microbiological Evaluation after Caries Removal by Various Burs. Int J Clin Pediatr Dent 2019;12(6):524-527.

Dermatoglyphics as a Noninvasive Tool for Predicting Dental Caries in Cerebral Palsy and Healthy Children: An In Vivo Study.

AIM: To find the association of dermatoglyphics and dental caries in normal and cerebral palsy (CP) children. MATERIALS AND METHODS: A total of 150 children of age group 6-12 years were selected and divided into three equal groups. Group I constituted of 50 CP caries-active children, group II constituted of 50 healthy caries active children, and group III consisted of 50 healthy caries-free children. World Health Organization (WHO) criteria were used for diagnosis and recording of decayed, missing, filled teeth (DMFT)/deft scores. Fingerprints of both hands were taken using a stamp pad and analyzed using the Cummin and Midlo method. RESULTS: The results were statistically analyzed using one-way analysis of variance (ANOVA) and post hoc Tukey's honestly significant difference (HSD). The data for the entire study were calculated using statistical package for social sciences (SPSS) statistical software 19.0 version. The mean DMFT/deft score was the highest for the CP caries-active group compared to the healthy caries-active and healthy caries-free children. Dermatoglyphic pattern distribution in the CP caries-active group showed more whorls and that in the healthy caries-free group showed more arches. Intergroup comparisons for DMFT/deft and dermatoglyphic patterns were significant except between CP caries-active children and healthy caries-active children. CONCLUSION: Association of dermatoglyphics and dental caries was observed among CP caries-active children, healthy caries-active children, and healthy caries-free children. This association can be helpful in identifying the possible genetic predisposition and early prediction of dental caries in CP children, so as to initiate oral health measures at an early stage. CLINICAL SIGNIFICANCE: Maintaining oral hygiene has always been a challenge in children because of many difficulties like behavior management and lack of dexterity, and it becomes all the more difficult in the case of children with special needs. Dermatoglyphics can be proven to be a very useful, noninvasive, and economical tool for the preliminary diagnosis of diseases of suspected genetic origin like dental caries and CP. HOW TO CITE THIS ARTICLE: Somani R, Gupta MP, et al. Dermatoglyphics as a Noninvasive Tool for Predicting Dental Caries in Cerebral Palsy and Healthy Children: An In Vivo Study. Int J Clin Pediatr Dent 2019;12(3):237-242.

Comparative Evaluation of Efficiency of Different File Systems in Terms of Remaining Dentin Thickness Using Cone-Beam Computed Tomography: An In vitro Study.

BACKGROUND: Endodontic therapy treats inside of the tooth and its success is based upon the triad of thorough canal debridement, effective disinfection, and obturation of the canal space. Thus, one of the most important steps is biomechanical preparation, which is the key stage of endodontic treatment with a predictive success factor if performed properly. AIM: The aim of the study is to evaluate and compare the cleaning efficiency of different file systems in terms of remaining dentin thickness. MATERIALS AND METHODS: A total of thirty permanent extracted anterior teeth were taken for the study and was divided into three groups - Group I - Manual Protapers, Group II - Rotary Mtwo, and Group III - Reciprocating WaveOne file systems. Pre-cone-beam computed tomography (CBCT) scan was taken followed by biomechanical preparation by the respective file groups. Post-CBCT scan was taken and the pre- and post-CBCT scans were compared for remaining dentin thickness. Data were analyzed with ANOVA (P = 0.001). STATISTICAL ANALYSIS USED: ANOVA test was used in this study. RESULTS: Protaper showed minimum reduction in dentin thickness followed by Mtwo and WaveOne showed maximum reduction in dentin thickness, but the intergroup comparison was found to be highly insignificant. CONCLUSION: WaveOne is a highly recommended rotary endodontic instrument which does not cause significant lowering in remaining dentin thickness after biomechanical preparation.

A biodegradable scaffold enhances differentiation of embryonic stem cells into a thick sheet of retinal cells.

Retinal degeneration is a leading cause of blindness in developed countries. Stem cells can be differentiated into retinal organoids to study mechanisms of retinal degeneration, develop therapeutic agents, and potentially serve as replacement tissues. The spherical nature of these retinoids limits their utility, because the investigator lacks ready access to both sides of the neo-tissue. For tissue-replacement, spherical retinoids are unable to interact simultaneously with the host retinal pigment epithelium and remaining neurosensory retina. To attempt making a planar retinoid, we developed a biodegradable scaffold that simulates the extracellular matrix of the neurosensory retina. Human embryonic stem cells were seeded on the scaffold. Differentiation into retinal cells was confirmed by quantitative RT-PCR, confocal immunocytochemistry, and immunoblotting. The scaffold favored differentiation into retinal cell types over other anterior forebrain cells, but retinal lamination was rudimentary. The cultures elicited a minimal immune response when implanted into the subretinal space of a mouse model of retinal degeneration. The implants survived for at least 12 weeks, but there was evidence of cytoplasmic transfer rather than implantation into the outer nuclear layer (photoreceptor layer). However, some implanted cells migrated to the inner layers of the retina and established elaborate arbors of neurites.

Herbal combat against E. faecalis - An in vitro study.

BACKGROUND: Herbs have renewed importance in this modern era for their antimicrobial properties and fewer side effects. So a novel idea to use these herbs for pulpectomy; was implemented. There are chances of failure of pulpectomy due to inefficient removal of microbial load. Thus, for a successful endodontic treatment, obturating material with optimum antimicrobial properties is advocated in the present study. AIM: To compare and evaluate the antibacterial efficacy of zinc oxide eugenol, zinc oxide with tulsi extract and zinc oxide with aloe vera as obturating materials against E. faecalis bacteria. MATERIALS AND METHODS: Antimicrobial efficacy of zinc oxide eugenol as control, zinc oxide with tulsi extract and zinc oxide with aloe vera as experimental groups were assessed by using agar diffusion method. The statistical analysis was done. RESULTS: Intergroup comparison revealed significant difference amongst all the groups except between zinc oxide eugenol and zinc oxide with tulsi extract. Zinc oxide eugenol had significantly higher zone of inhibition among all the groups. CONCLUSION: According to results obtained from the present study can be summarized as follows: Zinc oxide eugenol > Zinc oxide with tulsi extract > Zinc oxide with aloe vera.

Comparative evaluation of compressive strength, diametral tensile strength and shear bond strength of GIC type IX, chlorhexidine-incorporated GIC and triclosan-incorporated GIC: An in vitro study.

AIM: To comparatively evaluate the compressive strength, diametral tensile strength, and shear bond strength of glass ionomer cement type IX, chlorhexidine-incorporated glass ionomer cement, and triclosan-incorporated glass ionomer cement. MATERIALS AND METHODS: In this study, glass ionomer cement type IX was used as a control. Chlorhexidine diacetate, and triclosan were added to glass ionomer cement type IX powder, respectively, in order to obtain 0.5, 1.25, and 2.5% concentrations of the respective experimental groups. Compressive strength, diametral tensile strength, and shear bond strength were evaluated after 24 h using Instron Universal Testing Machine. The results obtained were statistically analyzed using the independent t-test, Dunnett test, and Tukey test. RESULTS: There was no statistical difference in the compressive strength, diametral tensile strength, and shear bond strength of glass ionomer cement type IX (control), 0.5% triclosan-glass ionomer cement, and 0.5% chlorhexidine-glass ionomer cement. CONCLUSION: The present study suggests that the compressive strength, diametral tensile strength, and shear bond strength of 0.5% triclosan-glass ionomer cement and 0.5% chlorhexidine-glass ionomer cement were similar to those of the glass ionomer cement type IX, discernibly signifying that these can be considered as viable options for use in pediatric dentistry with the additional value of antimicrobial property along with physical properties within the higher acceptable range.

Hyperbranched poly(glycidol)/poly(ethylene oxide) crosslinked hydrogel for tissue engineering scaffold using e-beams.

A microporous hydrogel scaffold was developed from hyperbranched poly(glycidol) (HPG) and poly(ethylene oxide) (PEO) using electron beam (e-beam) induced cross-linking for tissue engineering applications. In this study, HPG was synthesized from glycidol using trimethylol propane as a core initiator and cross-linked hydrogels were made using 0, 10, 20, and 30% HPG with respect to PEO. The effects of %-HPG on the swelling ratio, cross-linking density, mechanical properties, morphology, degradation, and cytotoxicity of the hydrogel scaffolds were then investigated. Increasing the HPG content increased the pore size of the hydrogel scaffold, as well as the porosity, elongation at break, degree of degradation and swelling ratio. In contrast, the presence of HPG decreased the cross-linking density of the hydrogel. There was no significant difference in compressive modulus and tensile strength of all compositions. The pore size of hydrogel scaffolds could be easily tailored by controlling the content of HPG in the polymer blend. Evaluation of the cytotoxicity demonstrated that HPG/PEO hydrogel scaffold has potential for use as a matrix for cellular attachment and proliferation. These results indicate that cross-linked HPG/PEO hydrogel can function as a potential material for tissue engineering scaffolds. Moreover, a facile method to prepare hydrogel microporous scaffolds for tissue engineering by e-beam irradiation was developed.

Comparative Evaluation of Shear Bond Strength of Various Glass Ionomer Cements to Dentin of Primary Teeth: An in vitro Study.

AIM: To evaluate and compare shear bond strength of various glass ionomer cements (GICs) to dentin of primary teeth. MATERIALS AND METHODS: Sample size taken for the study was 72 deciduous molars with intact buccal or lingual surfaces. Samples were randomly divided into three groups, i.e., groups A, B, and C and were restored with conventional type II GIC, type II light cure (LC) GIC, and type IX GIC respectively. Thermocycling was done to simulate oral conditions. After 24 hours, shear bond strength was determined using Instron Universal testing Machine at crosshead speed of 0.5 mm/ minute until fracture. Results were tabulated and statistically analyzed. RESULTS: It was found that the shear bond strength was highest in group B (LC GIC) 9.851 ± 1.620 MPa, followed by group C (type IX GIC) 7.226 ± 0.877 MPa, and was lowest in group A (conventional GIC) 4.931 ± 0.9735 MPa. CONCLUSION: Light cure GIC was significantly better than type IX GIC and conventional GIC in terms of shear bond strength. HOW TO CITE THIS ARTICLE: Somani R, Jaidka S, Singh DJ, Sibal GK. Comparative Evaluation of Shear Bond Strength of Various Glass Ionomer Cements to Dentin of Primary Teeth: An in vitro Study. Int J Clin Pediatr Dent 2016;9(3):192-196.

Poly(ethylene glycol) dicarboxylate/poly(ethylene oxide) hydrogel film co-crosslinked by electron beam irradiation as an anti-adhesion barrier.

The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC-5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33±6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03±0.01%) and the highest tissue adherence (75.67±1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®.

Remineralizing potential of various agents on dental erosion.

AIM: The purpose of this study is to compare the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, Tooth Mousse) containing and casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF, Tooth Mousse Plus) containing pastes on dental erosion. MATERIALS AND METHODS: Thirty permanent non-carious premolars indicated for orthodontic extraction were included in this study and were sectioned in mesiodistal direction vertically. After immersion in the carbonated drink for 14 min, samples were treated with various remineralizing pastes which were CPP-ACP containing paste (Tooth Mousse) and CPP-ACPF containing paste (Tooth Mousse Plus) according to the manufacturer's instructions. Vickers Microhardness was recorded at baseline, after exposure to erosive drink and after treatment with remineralizing pastes. Data obtained was statistically analysed using Student t-test with a level of significance set at p < 0.05. RESULTS: CPP-ACP (Tooth Mousse) and CPP-ACP with fluoride (Tooth Mousse Plus) resulted in 30.52% and 38.98% increase in post-erosion microhardness values respectively. The remineralizing potential of CPP-ACP with fluoride containing paste (Tooth Mousse Plus) was significantly better than that of CPP-ACP containing paste (Tooth Mousse) (p < 0.05). CONCLUSION: Casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF, Tooth Mousse Plus) can be recommended to be used in preventing erosive tooth wear from acidic beverages.

Engineering three-dimensional macroporous hydroxyethyl methacrylate-alginate-gelatin cryogel for growth and proliferation of lung epithelial cells.

Three-dimensional (3D) growth of cell is of particular interest in the field of tissue engineering and regenerative medicine. Scaffolds used for this purpose are often tailor-made to mimic the microenvironment and the extracellular matrix of the tissue with defined role such as to provide appropriate structural, chemical, and mechanical support. The aim of the study was to design the macroporous matrix with potential in the field of tissue engineering especially for lung muscle regeneration. Blend of hydroxyethyl methacrylate-alginate-gelatin (HAG) cryogel scaffold was synthesized using cryogelation technique and this polymer material combination is being reported first time. The rheology study showed the elastic property of the material in wet state with no variation in storage modulus (G'), loss modulus (G″), and phase angle upon temperature variation. The microcomputer tomography (micro-CT) analysis confirmed the homogenous polymer structure with average pore diameter of 84 µm. Scaffold synthesized using polymer combinations which is mixture of polysaccharide (alginate) and protein (gelatin) provides supportive environment for human lung epithelial cell proliferation confirmed by cytoskeletal stain phalloidin and nuclei staining 4',6-diamidino-2-phenylindole checked for over three weeks. The in vivo biocompatibility was further performed which showed integration of scaffold to the surrounding tissue with ability to recruit cells. However, at first week, small amount of infiltrating mast cells were found which subsequently diminished in following weeks. Immunohistochemistry for dendritic cells confirmed in vivo biocompatible nature of the HAG scaffold. The mechanical strength, stiffness, elastic measurements, in vivo compatibility, and in vitro lung cell proliferation show the potentiality of HAG materials for lung tissue engineering.

Modulated crosslinking of macroporous polymeric cryogel affects in vitro cell adhesion and growth.

Cell to matrix interactions affect in vitro cell adherence and proliferation and further decide the fate of tissue development for biomedical applications. This study demonstrates the role of crosslinking in altering the surface properties of 3D porous cryogel matrices. Glutaraldehyde and 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide crosslinkers are used separately for the crosslinking of alginate and gelatin (i.e., AG(G) and AG(EN)), respectively. The difference in crosslinking affects the physiochemical properties of these matrices leading to variable cell behavior as demonstrated using four different cell types, which show homogeneous cell growth in AG(G) and spheroid cell growth in AG(EN). The present study shows successful use of controlled crosslinking in directing the cell growth for tissue engineering.

Proliferation of chondrocytes on a 3-d modelled macroporous poly(hydroxyethyl methacrylate)-gelatin cryogel.

Tissue-engineering constructs should be designed to mimic the native tissue environment for cells, the scaffold matching to stiffness and strength of the tissues while maintaining an interconnected porous network and a reasonable porosity. This study presents a new single-step protocol for synthesis of a poly(hydroxyethyl methacrylate)-poly(ethylene glycol) diacrylate-gelatin (HPG) macroporous polymeric scaffold with well-controlled porous structure and good mechanical strength. The pore size of these matrices lies in the range of 30 to 100 µm with an average pore diameter of 80 µm and with an interconnected pore structure as analyzed by scanning electron microscopy. Further, interconnectivity was also confirmed by high solvent uptake capacity, as the cryogel reached its equilibrium within 2 min. The gels also showed substantial mechanical integrity, i.e., the average compressive modulus was 32.73 ± 2.36 kPa at 15% compression of their original length. The degree of weight loss of these cryogels was found to be approx. 88% within 8 weeks of incubation in PBS (pH 7.4) at 37°C. Physio-chemically optimized cryogel was further evaluated for in vitro growth and proliferation of isolated primary goat chondrocytes up to 3 weeks. The cell adherence on cryogel was examined by SEM analysis, while cell-matrix interaction was examined by 4-6-diamidino-2-phenylindole and propidium iodide staining. Furthermore, the cell compatibility and proliferation was evaluated using the MTT assay. Increase in total cellular metabolic activity was observed as shown by continuous increase in glycosaminoglycan and collagen contents with time. Collagen type-I and type-II gene expression analysed for over 3 weeks by RT-PCR showed the prominent expression of collagen type-II. These results suggest the use of synthesised cryogel scaffold as a matrix for chondrocyte attachment and proliferation in 3-D environment and as a delivery system in cartilage-tissue engineering.

Proliferation of myoblast skeletal cells on three-dimensional supermacroporous cryogels.

Cardiac and skeletal muscle tissue engineering provides a smart approach to overcome problems associated with organ transplantation and cardiac tissue and also lays a platform for superior alternative approaches in muscle regeneration. The aim of the study was to demonstrate cryogel scaffold potential in the field of skeletal muscle and cardiac tissue engineering. Poly-hydroxyethyl methacrylate (pHEMA)-gelatin cryogel scaffold was synthesized using cryogelation technique and such a designed material is being reported first time. Rheology study of the pHEMA-gelatin (HG) suggested that the cryogel scaffolds were stable at different temperatures and phase angle remained constant in both dry and wet state. HG cryogel was able to bear increased stress without leading to deformation. Monitoring the hydration of HG scaffold showed shift from a stiff to a more pliable material and upon continuing hydration, shear modulus remained constant with no further change observed. However, the change in phase angle <0.24 masculine indicates a gradual increase in stiffness of the material over time. Scaffold synthesised using such polymer combinations gave cells a native environment for proliferation and surface stiffness have shown to help in differentiation of the cells. Myoskeletal cell lines were cultured on these scaffolds to check the biocompatibility and cell proliferation. Alamar blue assay performed over a period of 3 weeks analysed the metabolic activity of cells which showed more than 60% increase in the total cellular activity. DNA content of cells was found to be directly related to number of cells present at a given time point and this was found to have increased by more than 50% in 3 weeks. Since in 3-D scaffold the surface area is more in comparison to 2-D, hence better cell proliferation is observed. Hoechst and DAPI staining showed tubular structure and alignment of the cells during formation of the tubules shows promising cellular response to the cryogel matrix. The mechanical strength, stiffness and elastic measurements of the scaffold indicated potential application of these materials for skeletal and cardiac tissue engineering.