The authors thank Dr. Ashish D Wadhwani. (Assistant Professor and Head, Department of Pharmaceutical Biotechnology, JSS College of Pharmacy, Ooty, India) for assisting in In vitro cell viability studies.
The authors would like to thank the Department of Science and Technology - Fund for Improvement of Science and Technology Infrastructure in Universities and Higher Educational Institutions (DST-FIST), New Delhi, for supporting our department.
The authors also like to thank Mr. Sanju. S and Mr. Sriram. Narukulla&#160;M. Pharm students for their support in the video shoot.
This research was supported by the JSS Academy of Higher Education &#38; Research (JSSAHER).

All the animal procedures performed were approved by the institutional animal ethical committee of JSS College of Pharmacy, Ooty, India.
1. Preparation of DOX loaded porous scaffolds by freeze-drying method
<ol>
	<li>Add 1.2 g of COL to 100 mL of water (e.g., Millipore) and keep aside for swelling.</li>
	<li>Stir the swollen COL dispersion at 2000 rpm overnight to ensure complete dissolution of COL.</li>
	<li>Prepare CS solution by dissolving approximately 0.8 g of CS in 100 mL of 1% acetic ...

<ol>
	<li>. IDF Diabetes Atlas, 9th edn Available from: <a target="_blank" href="https://www.diabetesatlas.org">https://www.diabetesatlas.org</a> (2019)</li><li>Falanga, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wound+healing+and+its+impairment+in+the+diabetic+foot.">Wound healing and its impairment in the diabetic foot.</a> The Lancet. 366 (9498), 1736-1743 (2005).</li><li>Frykberg, R. G., Banks, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+in+the+treatment+of+chronic+wounds.">Challenges in the treatment of chronic wounds.</a> Advances in Wound Care. 4 (9), 560-582 (2015).</li><li>Alexiadou, K., Doupis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Management+of+diabetic+foot+ulcers.">Management of diabetic foot ulcers.</a> Diabetes Therapy. 3 (1), 1-15 (2012).</li><li>Karri, V. V. S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+and+emerging+therapies+in+the+management+of+diabetic+foot+ulcers.">Current and emerging therapies in the management of diabetic foot ulcers.</a> Current Medical Research and Opinion. 32 (3), 519-542 (2016).</li><li>Sanapalli, B. 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M., Carvalho, E., de Sousa, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+on+the+development+of+wound+dressings+for+diabetic+foot+ulcer+treatment-a+review.">Recent advances on the development of wound dressings for diabetic foot ulcer treatment-a review.</a> Acta Biomaterialia. 9 (7), 7093-7114 (2013).</li><li>Natarajan, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanostructured+Lipid+Carriers+of+Pioglitazone+Loaded+Collagen/Chitosan+Composite+Scaffold+for+Diabetic+Wound+Healing.">Nanostructured Lipid Carriers of Pioglitazone Loaded Collagen/Chitosan Composite Scaffold for Diabetic Wound Healing.</a> Advances in Wound Care. 8 (10), 499-513 (2019).</li><li>Karri, V. V. S. 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I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+glucose+and+pH+on+uropathogenic+and+non-uropathogenic+Escherichia+coli:+studies+with+urine+from+diabetic+and+non-diabetic+individuals.">Effect of glucose and pH on uropathogenic and non-uropathogenic Escherichia coli: studies with urine from diabetic and non-diabetic individuals.</a> Journal of Medical Microbiology. 48 (6), 535-539 (1999).</li><li>Eloff, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+sensitive+and+quick+microplate+method+to+determine+the+minimal+inhibitory+concentration+of+plant+extracts+for+bacteria.">A sensitive and quick microplate method to determine the minimal inhibitory concentration of plant extracts for bacteria.</a> Planta Medica. 64 (8), 711-713 (1998).</li><li>Reddy, G. K., Enwemeka, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simplified+method+for+the+analysis+of+hydroxyproline+in+biological+tissues.">A simplified method for the analysis of hydroxyproline in biological tissues.</a> Clinical Biochemistry. 29 (3), 225-229 (1996).</li><li>Charulatha, V., Rajaram, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+different+crosslinking+treatments+on+the+physical+properties+of+collagen+membranes.">Influence of different crosslinking treatments on the physical properties of collagen membranes.</a> Biomaterials. 24 (5), 759-767 (2003).</li><li>Rehakova, M., Bako&#353;, D., Vizarova, K., Sold&#225;n, M., Jur&#237;ckov&#225;, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+collagen+and+hyaluronic+acid+composite+materials+and+their+modification+by+chemical+crosslinking.">Properties of collagen and hyaluronic acid composite materials and their modification by chemical crosslinking.</a> Journal of Biomedical Materials Research: An Official Journal of The Society for Biomaterials and The Japanese Society for Biomaterials. 30 (3), 369-372 (1996).</li><li>Chang, M. -. 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The main objective of this study was to determine the effect of DOX loaded COL-CS scaffold on DW healing in rats. CL and NCL were prepared and evaluated in terms of morphology, swelling index, in vitro release kinetics, and biocompatibility.
Characterization of the DOX loaded NCL and CL scaffold 
The prepared scaffolds were found to be porous with interconnected pores. These interconnected pores assure the porous, spongy nature that helps in the proper diffusion of oxygen...

Diabetes mellitus (DM) is a condition where the body&#39;s failure to deliver insulin or react to its outcomes in abnormal digestion of straightforward sugars brings about an upsurge of blood glucose 1. The most consecutive and crushing entanglement of DM is the diabetic wound (DW). Roughly 25% of patients with DM have the opportunity to build up a DW in their lifetime 1. The hindered healing of DW is accredited to a triopathy of DM: immunopathy, vasculopathy, and neuropathy. Whenever DW is left untreated, it may result in gangrene development, therefore prompting the removal of the concerned organ 2.
Plenty of treatments, such as instructing the patients (inspect wound daily, cleanse the wound, avoid activities that creates pressure on the wound, periodic glucose monitoring, etc.), controlling their blood glucose, wound debridement, pressure offloading, medical procedure, hyperbaric oxygen therapy, and advanced therapies are in practice&#160;3,4. The majority of these medications fail to address all prerequisites vital for DW care in light of the multifactorial pathophysiological conditions and unexpected expenses related to these medicines&#160;5. Even though the DW pathogenesis is multifactorial, the persistent inflammation with inappropriate tissue management is stated to be the actual reason for delayed healing in DWs 5,6.
Augmented levels of inflammatory and pro-inflammatory mediators in DW result in diminished growth factors responsible for delayed wound healing 2,6. Improper extracellular matrix (ECM) formation in DWs is accredited to increased levels of matrix metalloproteinases (MMPs) accountable for the rapid degradation of formed ECM. In MMPs, MMP-9 is reported as a major intermediary responsible for prolonged inflammation and rapid ECM degradation 7. It is stated that local treatment with an anti-inflammatory drug that decreases the elevated levels of MMP-9 re-establishes cutaneous homeostasis, framework arrangement and prompts better healing of DWs 8,9.
Doxycycline (DOX), an MMP-9 inhibitor, was chosen to suppress the elevated levels of MMP-9, a major inflammatory mediator responsible for persistent inflammation in DWs 10,11,12. In addition, DOX possess antioxidant (produce free hydroxy and phenoxy radicals capable of binding with reactive oxygen species) 13 and anti-apoptotic (inhibit caspase expression and mitochondrial stabilization) 14 activities that are essential for the treatment of DW. The arrangement of frameworks containing DOX, collagen (COL), and chitosan (CS) was chosen. The choice of COL depends on the way that it helps in providing the necessary framework responsible for mechanical strength and tissue regeneration 15. On the other hand, CS is structurally homologous to glycosaminoglycan, associated with several wound healing phases. It is also reported that CS holds significant anti-bacterial property 15. Hence, the COL/CS scaffold of DOX is formulated to suppress the prolonged inflammation, followed by supporting the matrix formation for successful wound healing in DM conditions.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1-ethyl-(3-3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC)</td>
			<td>Merck Millipore, Mumbai, India</td>
			<td>E7750</td>
			<td></td>
		</tr>
		<tr>
			<td>2-(N-morpholino) ethane sulfonic acid (MES)</td>
			<td>Merck Millipore, Mumbai, India</td>
			<td>137074</td>
			<td></td>
		</tr>
		<tr>
			<td>3-(4, 5 dimethyl thiazole-2 yl) -2, 5-diphenyl tetrazolium bromide (MTT)</td>
			<td>Thermo Fisher, Mumbai, India</td>
			<td>M6494</td>
			<td></td>
		</tr>
		<tr>
			<td>Deep freezer verticle</td>
			<td>Labline Instruments, Kochi, India</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dialysis sack</td>
			<td>Merck Millipore, Mumbai, India</td>
			<td>D6191-Avg. flat width 25 mm (1.0 in.), MWCO 12,000 Da</td>
			<td></td>
		</tr>
		<tr>
			<td>Doxycycline</td>
			<td>Sigma chemicals Co. Ltd, Mumbai, India</td>
			<td>D9891</td>
			<td></td>
		</tr>
		<tr>
			<td>Elisa kit</td>
			<td>R&#38;D Systems</td>
			<td>RMP900</td>
			<td></td>
		</tr>
		<tr>
			<td>Escherichia coli (E. coli)</td>
			<td>National Collection of Industrial Microorganisms, Pune, India</td>
			<td>NCIM 2567</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Merck Millipore, Mumbai, India</td>
			<td>100983</td>
			<td></td>
		</tr>
		<tr>
			<td>Lyophilizer-SZ042</td>
			<td>Sub-Zero lab instruments, Chennai, India</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mechanical Stirrer-RQ-122/D</td>
			<td>Remi laboratory instruments, Mumbai, India</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Medium molecular weight Chitosan</td>
			<td>Sisco Research Laboratories Pvt. Ltd., Mumbai, India</td>
			<td>18824</td>
			<td></td>
		</tr>
		<tr>
			<td>Microtome-RM2135</td>
			<td>Leica, U.K</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse embryonic fibroblast cells (3T3-L1)</td>
			<td>National Centre for Cell Sciences, Pune, India</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Multiple plate reader -Inifinte M200 Pro</td>
			<td>Tecan Instruments, Switzerland</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>N-hydroxy succinimide (NHS)</td>
			<td>Sigma chemicals Co. Ltd, Mumbai, India</td>
			<td>130672</td>
			<td></td>
		</tr>
		<tr>
			<td>Pseudomonas aeruginosa (P. aeruginosa)</td>
			<td>National Collection of Industrial Microorganisms, Pune, India</td>
			<td>NCIM 2036</td>
			<td></td>
		</tr>
		<tr>
			<td>Scanning Electron Microscopy (SEM)-S-4800</td>
			<td>Hitachi, India</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide (NaOH) pellets</td>
			<td>Qualigen fine chemicals, Mumbai, India</td>
			<td>Q27815</td>
			<td></td>
		</tr>
		<tr>
			<td>Staphylococcus aureus (S. aureus)</td>
			<td>National Collection of Industrial Microorganisms, Pune, India</td>
			<td>NCIM 5022</td>
			<td></td>
		</tr>
		<tr>
			<td>Staphylococcus epidermis (S. epidermis)</td>
			<td>National Collection of Industrial Microorganisms, Pune, India</td>
			<td>NCIM 5270</td>
			<td></td>
		</tr>
		<tr>
			<td>Streptozotocin (STZ)</td>
			<td>Sisco Research Laboratories Pvt. Ltd., Mumbai, India</td>
			<td>14653</td>
			<td></td>
		</tr>
		<tr>
			<td>Type-1 rat Collagen</td>
			<td>Sigma chemicals Co. Ltd, Mumbai, India</td>
			<td>C7661</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultraviolet&#8211;visible spectroscopy-1700</td>
			<td>Shimadzu</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

doxycycline loaded collagen-chitosan composite scaffold for the accelerated healing of diabetic wounds

One major complication of diabetes mellitus is diabetic wounds (DW). The prolonged phase of inflammation in diabetes obstructs the further stages of an injury leading to delayed wound healing. We selected doxycycline (DOX), as a potential drug of choice, due to its anti-bacterial properties along with its reported anti-inflammatory properties. The current study aims to formulate DOX loaded collagen-chitosan non-crosslinked (NCL) &amp; crosslinked (CL) scaffolds and evaluate their healing ability in diabetic conditions. The characterization result of scaffolds reveals that the DOX-CL scaffold holds ideal porosity, a low swelling &amp; degradation rate, and a sustained release of DOX compared to the DOX-NCL scaffold. The in vitro studies reveal that the DOX-CL scaffold was biocompatible and enhanced cell growth compared with CL scaffold treated and control groups. The anti-bacterial studies have shown that the DOX-CL scaffold was more effective than the CL scaffold against the most common bacteria found in DW. Using the streptozotocin and high-fat diet-induced DW model, a significantly (p&#8804;0.05) faster rate of wound contraction in the DOX-CL scaffold treated group was observed compared to those in CL scaffold treated and control groups. The use of the DOX-CL scaffold can prove to be a promising approach for local treatment for DWs.

Characterization of the DOX loaded NCL and CL scaffold 
On visual examination, the NCL and CL scaffold was found to be cream in color. Besides, both the scaffolds appear to be like a sponge, stiff and inelastic when examined physically. SEM images of the NCL and CL scaffolds are shown in Figure 1. From the figure, it was clear that there was a decrease in pore size after crosslinking by forming intermolecular linkages. Also, the NCL and CL scaffolds porosity were found ...

Watch this Scientific Journal Video about Doxycycline Loaded Collagen-Chitosan Composite Scaffold for the Accelerated Healing of Diabetic Wounds at JoVE.com

Doxycycline Loaded Collagen-Chitosan Composite Scaffold for the Accelerated Healing of Diabetic Wounds

The prepared DOX-CL scaffold satisfied the prerequisites of an ideal DW dressing in mechanical strength, porosity, water absorption, degradation rate, sustained release, anti-bacterial, biocompatibility, and anti-inflammatory properties, which are considered to be essential for the recovery of damaged tissue in DWs.

One major complication of diabetes mellitus is diabetic wounds (DW). The prolonged phase of inflammation in diabetes obstructs the further stages of an ...

The current research work is doxycycline loaded collagen-chitosan composite scaffolds for the accelerated healing of diabetic wounds. Diabetes is a chronic metabolic disease characterized by elevated levels of blood glucose. The longer the time individual have diabetes, the higher the risk of complications, such as cardiovascular disease, nephropathy, neuropathy, retinopathy, and foot damage, et cetera.Nerve damage in the feet and also poor blood flow to the feet increase the risk of various foot complications. If left untreated these wounds may ultimately require toe, foot, or leg amputations. Roughly, 25%patients with diabetes mellitus have the opportunity to build up a diabetic wound in their lifetime.The therapeutic management of diabetic wounds remains a hurdle to date which needs to be eventually crossed. Even though the pathophysiology of diabetic wound is multifactorial, it is believed that local treatment with anti-inflammatory drugs could decrease the elevated levels of MMP-9 and reestablishes the cutaneous homeostasis framework arrangement and prompts healing in diabetic wounds. Doxycycline, the MMP-9 inhibitor, was chosen in this study to suppress these elevated levels of MMP-9, a major inflammatory molecule responsible for the continued inflammation of diabetic wounds.On the other hand, biomaterials have fascinated humans for several decades and have been at the core of many game-changing medical breakthroughs for efficient drug and macromolecular delivery and development of tailor-made biomedical devices. Hence, with this brief introduction, we have prepared a doxycycline loaded collagen-chitosan scaffold to attenuate, to accelerate the delayed healing in diabetic wounds. This is Bharat Kumar Reddy, research scholar from Department of Pharmaceutics, JSS College of Pharmacy, Ooty, India.Today we are here to look into the procedure, how to prepare doxycycline loaded collagen-chitosan scaffold for the accelerated healing of diabetic wounds. Let's have a glimpse into the procedure, how to prepare. We are going to prepare 1.2%of collagen solution, for which we are taking 1.2 grams of Type-I collagen, which is from rat tail origin.To this, we are adding 100 ml of Millipore water and kept it aside for half an hour in order to allow the collagen to get bulge in water. In the next step, 0.8%of chitosan solution was prepared, for which we are taking 0.8 grams of medium molecular weight chitosan, and this was mixed with 100 ml of 1%acetic acid. This solution also, we have kept aside for half an hour.After half an hour, both the solutions were subjected for mechanical stirring overnight at an RPM of 2000. To the overnight stirred collagen solution we are slowly adding one gram of doxycycline. And the solution containing this collagen and doxycycline was subjected for half an hour of stirring at an RPM of 2000.To this solution we are slowly adding overnight stirred chitosan solution. And this, make sure it's labeled as physical mixture which contains doxycycline, collagen, chitosan. This physical mixture we have subjected for another half an hour of stirring at an RPM of 2000.After half an hour these physical mixture were transferred into to respective aluminum molds, which is having a dimensions of two into two centimeter and a thickness of 0.5 centimeter. Later, these molds were transferred into a metal container. These metal container was containing the aluminum molds, was subjected for deep freezing.After 24 hours, we can clearly see the solidified physical mixture containing doxycycline, collagen, and chitosan. These solidified physical mixture was further subjected for lyophilization. The lyophilization was performed at minus 85 degrees plus or minus four degree Celsius for 72 hours.After 72 hours, the lyophilized material were taken out from the lyophilizer. And here we can clearly see the completely dried physical mixture, which is nothing but known as doxycycline loaded collagen-chitosan scaffold. These scaffolds were subjected for crosslinking In order to perform crosslinking, initially, MES buffer was prepared by taking 0.488 grams of MES and 15 ml of water, from which we are taking out 20 ml of MES buffer and transferring separately into your beaker.To these 20 ml of beaker, 50 mg of doxycycline loaded collagen-chitosan was added. And the soaking of this scaffold was performed for half an hour. After half an hour, the doxycycline loaded collagen-chitosan scaffold was taken out from the 20 ml MES buffer.Further, it was soaked in a solution containing 19.5 ml of MES buffer, 0.1264 grams of EDC, and 0.014 grams of NHS. The soaking was performed for four hours time interval for the completion of crosslinking. After crosslinking, the crosslinked doxycycline loaded collagen-chitosan scaffold was taken out from the solution and transferred it into a container, which was detailed in the procedure before, and it was dried separately.Here we can clearly see the non-crosslinked and crosslinked scaffold, along with the same images. From the images it is clear that crosslinking of the scaffold resulted in decreased pore size due to the formation of strong intramolecular bonds. Male Wistar rat was taken and the two into two centimeter mark was drawn on the dorsal thoracic region.Excision wound was created around the mark and wound tracing was taken on a OHP sheet. The trace of the wound was measured with the help of graphical method. The wound created on the animal was around 176 mm.Later, the created wound was treated with crosslinked doxycycline loaded collagen-chitosan scaffold with the primary dressing and monitored for 21 days. Once the animal was recovered from the anesthesia, each animal were caged individually. And these animals were are fed with normal diet and water.All the animals, after creating the wound, were divided into three groups in which each group contained six animals. Here we can clearly see the difference between zero day and seven day in which doxycycline loaded crosslinked scaffold wound reduction was around 48%And in this image we can clearly see the difference between the day 14 and day 21 of all the groups in which doxycycline loaded collagen crosslinked scaffold was healed around 99%The healed area was isolated and processed for histopathologic studies with the help of HMB staining. Here we can clearly see the reepithelized epidermis, on day 21, in the doxycycline loaded collagen chitosan scaffold.Whereas in the control and crosslinked scaffold, nothing but placebo, still the epidermis had to be formed. Like our own study, the prepared doxycycline crosslinked scaffolds has exhibited many ideal properties, such as good mechanical strength, biocompatibility, sustained release water absorption, along with antibacterial and anti-inflammatory properties. These scaffolds can be an ideal dosis form for the treatment of diabetic wounds.

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Research

JoVE Journal

Bioengineering

4.2K ビュー.  JSS Academy of Higher Education & Research. 現在の研究は、糖尿病性創傷の加速治癒のためのドキシサイクリン装填されたコラーゲンキトサン複合足場である。糖尿病は、血糖のレベルの上昇を特徴とする慢性代謝疾患である。糖尿病を持つ時間が長ければ長いほど、心血管疾患、腎症、神経障害、網膜症、足の損傷などの合併症のリスクが高くなります。足の神経損傷と足への血流の悪さは、様々な足の合?...