Wound management and healing in several physiological or pathological conditions, particularly when comorbidities are involved, usually proves to be difficult. This presents complications leading to socio-economic and public health burdens. The accelerative wound healing potential of biocompatible poly(3-hydroxyalkanoates)-co-(6-hydroxyhexanoate) (PHA-PCL) composite hydrogel is reported herein. The biosynthesized PHA-PCL macromer was cross-linked with PEGMA to give a hydrogel. Twenty-four rats weighing 200-250 g each were randomly assigned to four groups of six rats. Rats in group I (negative control) were dressed with sterilized gum acacia paste in 10% normal saline while PEGMA-alone hydrogel (PH) was used to dress group II (secondary control) rats. Group III rats were dressed with PHAs-PCL cross-linked PEGMA hydrogel (PPH). For the positive control (group IV), the rats were dressed with Intrasite(®) gel. Biochemical, histomorphometric and immunohistomorphometric analyses revealed a significant difference in area closure and re-epithelialization on days 7 and 14 in PPH or Intrasite(®) gel groups compared to gum acacia or PEGMA-alone groups. Furthermore, wounds dressed with PPH or Intrasite(®) gel showed evident collagen deposition, enhanced fibrosis and extensively organized angiogenesis on day 14 compared to the negative control group. While improvement in wound healing of the PH dressed group could be observed, there was no significant difference between the negative control group and the PH dressed group in any of the tests. The findings suggested that topical application of PPH accelerated the rats' wound healing process by improving angiogenesis attributed to the increased microvessel density (MVD) and expressions of VEGF-A in tissue samples. Thus, PPH has been demonstrated to be effective in the treatment of cutaneous wounds in rats, and could be a potential novel agent in the management and acceleration of wound healing in humans and animals.
Interconnected porous tricalcium phosphate ceramics are considered to be potential bone substitutes. However, insufficient mechanical properties when using tricalcium phosphate powders remain a challenge. To mitigate these issues, we have developed a new approach to produce an interconnected alpha-tricalcium phosphate (α-TCP) scaffold and to perform surface modification on the scaffold with a composite layer, which consists of hybrid carbonate apatite / poly-epsilon-caprolactone (CO3Ap/PCL) with enhanced mechanical properties and biological performance. Different CO3Ap combinations were tested to evaluate the optimal mechanical strength and in vitro cell response of the scaffold. The α-TCP scaffold coated with CO3Ap/PCL maintained a fully interconnected structure with a porosity of 80% to 86% and achieved an improved compressive strength mimicking that of cancellous bone. The addition of CO3Ap coupled with the fully interconnected microstructure of the α-TCP scaffolds coated with CO3Ap/PCL increased cell attachment, accelerated proliferation and resulted in greater alkaline phosphatase (ALP) activity. Hence, our bone substitute exhibited promising potential for applications in cancellous bone-type replacement.
Polyhydroxyalkanoate (PHA) is a microbial polymer that has been at the forefront of many attempts at tissue engineering. However, the surface of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) is hydrophobic with few recognition sites for cell attachment. Various concentrations of fish-scale collagen peptides (FSCPs) were incorporated into P(3HB-co-4HB) copolymer by aminolysis. Later, FSCPs were introduced onto the aminolyzed P(3HB-co-4HB) scaffolds. Introduction of the FSCP groups was verified using Fourier transform infrared spectroscopy and the ninhydrin method. The effect of the incorporation of FSCPs on hydrophilicity was investigated using the water contact angle. As the concentration of FSCPs increased, the water contact angle decreased. In vitro study demonstrated that P(3HB-co-4HB)/FSCP scaffolds provided better cell attachment and growth of L929 mouse fibroblast cells and better cell proliferation. In vivo study showed that P(3HB-co-4HB)/1.5 wt% FSCPs had a significant effect on wound contractions, with the highest percentage of wound closure (61%) in 7 d.
In this in vivo study, Sprague Dawley (SD) rats were used to investigate the bioactivity as well as the microstructural and mechanical properties of Ti-6Al-4V samples embedded with hydroxyapatite (HA) using two different coating methods-superplastic embedment (SPE) and superplastic deformation (SPD). The HA layer thickness for the SPE and SPD samples increased from 249.1 ± 0.6 nm to 874.8 ± 13.7 nm, and from 206.1 ± 5.8 nm to 1162.7 ± 7.9 nm respectively, after 12 weeks of implantation. The SPD sample exhibited much faster growth of newly formed HA compared to SPE. The growth of the newly formed HA was strongly dependent on the degree of HA crystallinity in the initial HA layer. After 12 weeks of implantation, the surface hardness value of the SPE and SPD samples decreased from 661 ± 0.4 HV to 586 ± 1.3 HV and from 585 ± 6.6 HV to 425 ± 86.9 HV respectively. The decrease in surface hardness values was due to the newly formed HA layer that was more porous than the initial HA layer. However, the values were still higher than the substrate surface hardness of 321 ± 28.8 HV. Wear test results suggest that the original HA layers for both samples were still strongly intact, and to a certain extent the newly grown HA layers also were strongly bound with the original HA layers. This study confirms the bioactivity and mechanical stability of the HA layer on both samples in vivo.
Mesoporous bioactive glass containing 1% Ga2O3 (1%Ga-MBG) is attractive for hemorrhage control because of its surface chemistry which can promote blood-clotting. The present study compares this proprietary inorganic coagulation accelerator with two commercial hemostats, CeloxTM (CX) and QuikClot Advanced Clotting Sponge PlusTM (ACS+). The results indicate that the number of adherent platelets were higher on the 1%Ga-MBG and CX surfaces than ACS+ whereas a greater contact activation was seen on 1%Ga-MBG and ACS+ surfaces than CX. 1%Ga-MBG not only resulted in larger platelet aggregates and more extensive platelet pseudopodia compared to CX and ACS+ but also significantly accelerated the intrinsic pathways of the clotting cascade. In vitro thrombin generation assays also showed that CX and ACS+ induced low levels of thrombin formation while 1%Ga-MBG had significantly higher values. 1%Ga-MBG formed a larger red blood cell aggregate than both CX and ACS+. Direct exposure of 1%Ga-MBG to fibroblast cells increased cell viability after 3 days relative to CX and ACS+, inferring excellent cytocompatibility. The results of this study promote 1%Ga-MBG as a promising hemostat compared to the commercially available products as it possesses essential factors required for coagulation activation.
Chitin ranks next to cellulose as the most important bio-polysaccharide which can primarily be extracted from crustacean shells. However, the emergence of new areas of the application of chitin and its derivatives are on the increase and there is growing demand for new chitin sources. In this study, therefore, an attempt was made to extract chitin from the house cricket (Brachytrupes portentosus) by a chemical method. The physicochemical properties of chitin and chitosan extracted from crickets were compared with commercial chitin and chitosan extracted from shrimps, in terms of proximate analysis in particular, of their ash and moisture content. Also, infrared spectroscopy, x-ray diffraction (XRD), scanning electron microscopy and elemental analysis were conducted. The chitin and chitosan yield of the house cricket ranges over 4.3%-7.1% and 2.4%-5.8% respectively. Chitin and chitosan from crickets compares favourably with those extracted from shrimps, and were found to exhibit some similarities. The result shows that cricket and shrimp chitin and chitosan have the same degree of acetylation and degree of deacetylation of 108.1% and 80.5% respectively, following Fourier transform infrared spectroscopy. The characteristic XRD strong/sharp peaks of 9.4 and 19.4° for α-chitin are common for both cricket and shrimp chitin. The percentage ash content of chitin and chitosan extracted from B. portentosus is 1%, which is lower than that obtained from shrimp products. Therefore, cricket chitin and chitosan can be said to be of better quality and of purer form than commercially produced chitin and chitosan from shrimp. Based on the quality of the product, chitin and chitosan isolated from B. portentosus can replace commercial chitin and chitosan in terms of utilization and applications. Therefore, B. portentosus is a promising alternative source of chitin and chitosan.
Titainum (Ti) implants have been successfully used in orthopaedic and dental surgery. However, the poor early bone tissue integration is still a common failure. This could be modulated by improving material bonding or adhesion directly to bone though a surface roughening and/or a bioresorbable and osteoconductive coating. In this study, we report on the biological behavious of the Ti substrate with modified surface roughness and/or bioactive coating. The roughened Ti surface was prepared by acid etching reaction, and the calcium carbonate (CaCO3) coating on the substrates was synthesized by hydrothermal treatment of Ti in calcium citrate complexes. The study demonstrated that surface roughing of Ti alone did not improve the biological reponse of the MC3T3-E1 cells, however, CaCO3 coating on smooth Ti surface increased cell responses, and the affects were further enhanced in combination with Ti surface roughening. Larger cell area, greater cell proliferation and increased bone-like nodule formation were obtained on the CaCO3 coating of the roughened Ti surface. This was also supported by a higher ALP value obtained for the the coatings of roughened Ti surface. The cell behaviours found in the current study support further development of calcium carbonate coatings towards clinical application.
Gemcitabine is used to treat various cancers like breast, pancreatic, non-small lung carcinoma, ovarian, bladder and cervical cancers. Gemcitabine (GEM), however, has the problems of non-selectivity. Water-soluble, fluorescent and mono-dispersed carbon dots (CDs) were fabricated using sucrose by ultrasonic method. CDs were further conjugated with GEM through amide linkage. The physical and morphological properties of these carbon dots-gemcitabine conjugates (CDs-GEM) were determined using different analytical techniques. In vitro cytotoxicity and apoptosis studies of CDs-GEM conjugates were evaluated by various bioactivity assays on human cell lines, MCF-7 (human breast adenocarcinoma) and HeLa (cervical cancer) cell lines. Results of kinetic studies have shown maximum drug loading efficacy of 17.0 mg of GEM per 50.0 mg of CDs. CDs were found biocompatible, and the CDs-GEM conjugates exhibited excellent bioactivity and exerted potent cytotoxicity against tumor cells with IC50 value of 19.50 μg/mL in HeLa cells which is lower than the IC50 value of pure GEM (~20.10 μg/mL). In vitro studies on CDs-GEM conjugates demonstrated the potential to replace the conventional administration of GEM. The CDs-GEM conjugates are more stable, have higher aqueous solubility and are more cytotoxic as compared to GEM alone. The CDs-GEM conjugates show reduced side effects to the normal cells along with excellent cellular uptake. Hence, CDs-GEM conjugates are more selective towards cancerous cell lines as compared to non-cancerous cells. Also, CDs-GEM conjugates successfully induced early and late apoptosis in cancer cell lines and might be effective and safe to use for in vivo applications.
Cancer is the leading cause of death worldwide. Capecitabine (CP) shows severe side effects because of early metabolism in stomach that affects the normal cells and organs, particularly liver and stomach. In this scope, we report the biocompatible, nontoxic polymeric thin films loaded with anti-cancer drug, CP for target specific, sublingual delivery of CP. Chitosan (CS) and polyvinyl alcohol (PVA) were used as biodegradable polymers alongwith glutaraldehyde (GLA) cross linker. CP-loaded thin films (TFCP1-TFCP5) were fabricated by solvent casting method. The results of Fourier transform infrared spectroscopy confirmed the presence of CP and polymers (CS and PVA) with GLA which binds through hydrogen bonding, and compatibility of drug with different excipients. Thermogravemetric analysis showed that the thin films are highly stable while differential scanning calorimeter thermograms confirmed the complete miscibility/entrapment of CP within PVA/CS thin film matrix. X-ray diffraction patterns revealed the molecular ineractions between CP and polymer matrix. High degree of swelling index of thin films at pH 7.4 was observed in comparison to pH 5.5. CP release studies in acetate (pH 5.5) and phosphate buffer (pH 7.4) showed that the thin films swell and result in drug diffusion faster in phosphate buffer through diffusion governed by Higuchi's model. Cytotoxicity results displayed that CPTFs killed MCF-7 and T47D (human breast adenocarcinoma) cells more effectively as compared to CP alone. The results of adhesion assay also showed that the PVA and CS both are safe and biocompatible. TFCP1 and TFCP3 thin films efficiently induced the apoptosis as compared to CP alone. The improved ability of TFCP1 and TFCP3 to induce cytotoxicity in MCF-7 cells reflects the potential of these thin films for targeted drug delivery. The CPTFs were stable for 4 months at 4 °C/60% ± 2%RH and 25 °C/70% ± 2%RH. In conclusion, the thin film formulations showed target specific controlled and burst release properties and thus could prove to be effective for human breast cancer treatment.