Characterization of bionanocomposite scaffolds comprised of mercaptoethylamine-functionalized gold nanoparticles crosslinked to acellular porcine tissue.

Bionanocomposite scaffolds comprised of nanomaterials and the extracellular matrix (ECM) of porcine diaphragm tissue capitalizes on the benefits of utilizing a natural ECM material, while also potentially enhancing physicomechanical properties and biocompatibility through nanomaterials. Gold nanoparticle (AuNP) bionanocomposite scaffolds were subjected to a number of characterization techniques to determine whether the fabrication process negatively impacted the properties of the porcine diaphragm tissue and whether the AuNP improved the properties of the tissue. Tensile testing and differential scanning calorimetry demonstrated that the bionanocomposite possessed improved tensile strength and thermal stability relative to natural tissue. The collagenase assay and Fourier transform infrared spectroscopy additionally confirmed that denaturation of the collagen of the ECM did not occur. The novel bionanocomposite scaffold possessed properties similar to commercially available scaffolds and will be further developed for soft tissue applications such as hernia repair through in vivo studies in an animal model.

Early results of midline hernia repair using a minimally invasive component separation technique.

A minimally invasive component separation may lead to a dynamic abdominal wall after hernia repair, with reduced complications. We present early results of our patients undergoing this technique. Five patients were selected for open midline repairs; three with chronic infections, one with a prior midline skin graft, and one who desired a primary, tension-free repair. These three males and two females had a mean age of 50.8 +/- 21.1 years and body mass index of 30.9 +/- 6.2. The mean number of previous abdominal operations was 7 +/- 3.4 and previous attempted hernia repairs were 4 +/- 2.7. All patients had a midline laparotomy with lysis of adhesions. An endoscopic component separation was then performed bilaterally. Drains were left in the dissection bed. All patients had the midline closed; four received biologic mesh underlays. Mean operative time was 227 minutes +/- 49. Mean length of stay (LOS) was 9.2 days +/- 3.6. Early median follow-up was 6 months (range 0.25-9). Two patients required postop transfusions, and two patients had mild complications of the midline wound (hematoma, infection). To date, one recurrence was diagnosed by CT scan. Early evaluation of adopting the minimally invasive (MIS) component separation demonstrates minimal complications and good initial outcomes.

Catamenial appendicitis.

BACKGROUND: Reproductive-aged women undergoing appendectomy for suspected appendicitis have twice the rate of negative histology as age-matched men. The reason for this discrepancy is unknown. CASES: Three patients with peritoneal endometriosis and recurrent symptoms of acute appendicitis coincident with menses underwent resection of a noninflamed appendix with long-term symptom resolution. Standard pathological evaluation failed to demonstrate evidence of appendiceal endometriosis or appendicitis. Additional evaluation demonstrated a marked increase in number of mast cells in the appendiceal muscularis compared with normal appendices. CONCLUSION: The term "catamenial appendicitis" has been coined to describe these cases, and a mechanism of pathogenesis of right lower quadrant pain and nausea in patients with histologically confirmed endometriosis is proposed.

Integrated flexible endoscopy training during surgical residency.

BACKGROUND: New advances in endoscopic surgery make it imperative that future gastrointestinal surgeons obtain adequate endoscopy skills. An evaluation of the 2001-02 general surgery residency endoscopy experience at the University of Missouri revealed that chief residents were graduating with an average of 43 endoscopic cases. This met American Board of Surgery (ABS) and Accreditation Council for Graduate Medical Education (ACGME) requirements but is inadequate preparation for carrying out advanced endoscopic surgery. Our aim was to determine if endoscopy volume could be improved by dedicating specific staff surgeon time to a gastrointestinal diagnostic center at an affiliated Veterans Administration Hospital. METHODS: During the academic years 2002-05, two general surgeons who routinely perform endoscopy staffed the gastrointestinal endoscopy center at the Harry S. Truman Hospital two days per week. A minimum of one categorical surgical resident participated during these endoscopy training days while on the Veterans Hospital surgical service. A retrospective observational review of ACGME surgery resident case logs from 2001 to 2005 was conducted to document the changes in resident endoscopy experience. The cases were compiled by postgraduate year (PGY). RESULTS: Resident endoscopy case volume increased 850% from 2001 to 2005. Graduating residents completed an average of 161 endoscopies. Endoscopic experience was attained at all levels of training: 26, 21, 34, 23, and 26 mean endoscopies/year for PGY-1 to PGY-5, respectively. CONCLUSIONS: Having specific endoscopy training days at a VA Hospital under the guidance of a dedicated staff surgeon is a successful method to improve surgical resident endoscopy case volume. An integrated endoscopy training curriculum results in early skills acquisition, continued proficiency throughout residency, and is an efficient way to obtain endoscopic skills. In addition, the foundation of flexible endoscopic skill and experience has allowed early integration of surgery residents into research efforts in natural orifice transluminal endoscopic surgery.

Management of anastomotic leaks after Roux-en-Y bypass using self-expanding polyester stents.

BACKGROUND: To analyze the outcomes of a series of endoscopically placed polyester self-expanding polyflex stents (SEPSs) for the management of anastomotic leaks after Roux-en-Y bypass. Anastomotic leaks after gastric bypass cause significant morbidity and mortality. Covered polyester SEPSs might have a role in the treatment of these leaks. METHODS: A retrospective chart review was performed from January 2006 to November 2006 that included all acute and chronic leaks treated with SEPSs. RESULTS: A total of 6 patients were treated with stents, with a mean procedure time of 22 minutes. Of these 6 patients, 5 had acute postoperative leaks and 1 had a chronic fistula. Five patients started oral intake 1-6 days after their procedure. All acute leaks had complete healing at a median of 44 days. The patient with a chronic gastrocutaneous fistula required revisional surgery for fistula closure. In addition, 5 patients had stent migration, and 3 required stent replacement. CONCLUSION: An endoscopically placed SEPS provides a less-invasive alternative to treat acute anastomotic leaks after Roux-en-Y bypass while simultaneously allowing oral intake. The results of this case series have demonstrated this treatment to be safe and effective.

Increased plasma interleukin 6 concentrations and exaggerated adipose tissue interleukin 6 content in severely obese patients after operative trauma.

BACKGROUND: The cytokine response to operative trauma may be altered in obesity. Thus, we monitored changes in systemic and adipose tissue content of interleukin 6 (IL-6) and in insulin resistance in nonobese versus severely obese patients before and immediately after abdominal operations. METHODS: At the beginning and the end of operation, blood samples and biopsies consisting of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were collected from 13 nonobese and 33 severely obese patients. Systemic concentrations of glucose, insulin, and IL-6, as well as adipose tissue content of IL-6, were determined. RESULTS: Plasma IL-6 concentration and adipose tissue content of IL-6 increased, compared with baseline in patients after operation (plasma, 13- and 5.7-fold; VAT, 270- and 210-fold; SAT, 79- and 8.2-fold in severely obese vs nonobese patients, respectively). The increase in IL-6 in plasma and in both VAT and SAT was exaggerated in severely obese patients, compared with nonobese patients. Increases after operation in plasma IL-6 concentrations were correlated positively to the corresponding increases in both SAT and VAT IL-6 content (r = 0.57 and 0.66, respectively). Also, we found a positive correlation between the worsening of insulin resistance and increases in both plasma and SAT IL-6 concentrations (r = 0.40 and 0.51, respectively). CONCLUSIONS: Circulating IL-6 concentrations both at baseline and after operation are related strongly to abdominal adipose tissue content of content of IL-6 and are exaggerated in severely obese persons. After operation, worsening of insulin resistance is associated with increasing plasma and adipose tissue content of IL-6.

Materials characterization of explanted polypropylene hernia mesh: Patient factor correlation.

This study quantitatively assessed polypropylene (PP) hernia mesh degradation and its correlation with patient factors including body mass index, tobacco use, and diabetes status with the goal of improving hernia repair outcomes through patient-matched mesh. Thirty PP hernia mesh explants were subjected to a tissue removal process followed by assessment of their in vivo degradation using Fourier transform infrared, differential scanning calorimetry, and thermogravimetric analysis analyses. Results were then analyzed with respect to patient factors (body mass index, tobacco use, and diabetes status) to determine their influence on in vivo hernia mesh oxidation and degradation. Twenty of the explants show significant surface oxidation. Tobacco use exhibits a positive correlation with modulated differential scanning calorimetry melt temperature and exhibits significantly lower TGA decomposition temperatures than non-/past users. Chemical and thermal characterization of the explanted meshes indicate measurable degradation while in vivo regardless of the patient population; however, tobacco use is correlated with less oxidation and degradation of the polymeric mesh possibly due to a reduced inflammatory response.

Surgical Site Infiltration for Abdominal Surgery: A Novel Neuroanatomical-based Approach.

BACKGROUND: Provision of optimal postoperative analgesia should facilitate postoperative ambulation and rehabilitation. An optimal multimodal analgesia technique would include the use of nonopioid analgesics, including local/regional analgesic techniques such as surgical site local anesthetic infiltration. This article presents a novel approach to surgical site infiltration techniques for abdominal surgery based upon neuroanatomy. METHODS: Literature searches were conducted for studies reporting the neuroanatomical sources of pain after abdominal surgery. Also, studies identified by preceding search were reviewed for relevant publications and manually retrieved. RESULTS: Based on neuroanatomy, an optimal surgical site infiltration technique would consist of systematic, extensive, meticulous administration of local anesthetic into the peritoneum (or preperitoneum), subfascial, and subdermal tissue planes. The volume of local anesthetic would depend on the size of the incision such that 1 to 1.5 mL is injected every 1 to 2 cm of surgical incision per layer. It is best to infiltrate with a 22-gauge, 1.5-inch needle. The needle is inserted approximately 0.5 to 1 cm into the tissue plane, and local anesthetic solution is injected while slowly withdrawing the needle, which should reduce the risk of intravascular injection. CONCLUSIONS: Meticulous, systematic, and extensive surgical site local anesthetic infiltration in the various tissue planes including the peritoneal, musculofascial, and subdermal tissues, where pain foci originate, provides excellent postoperative pain relief. This approach should be combined with use of other nonopioid analgesics with opioids reserved for rescue. Further well-designed studies are necessary to assess the analgesic efficacy of the proposed infiltration technique.

Components separation technique and laparoscopic approach: a review of two evolving strategies for ventral hernia repair.

When faced with large ventral hernias, surgeons frequently must choose between higher incidence of recurrence after primary repair and higher incidence of wound complications after repair with mesh. The aim of this study is to compare early outcomes between laparoscopic repair (LR) and components separation technique (CST), two evolving strategies for the management of large ventral hernias. We reviewed 42 consecutive patients who underwent CST and 45 consecutive patients who underwent LR of ventral hernia defects of at least 12 cm2. Demographics, hernia characteristics, and short-term outcomes were compared between groups. Patients in the LR group were younger (53 +/- 2 vs 68 +/- 2 years, P < 0.0001), had greater body mass index (34 +/- 2 vs 29 +/- 1 kg/m2, P = 0.02), and had larger hernia defects (318 +/- 49 vs 101 +/- 16 cm2, P < 0.0001) than patients in the CST group. The LR resulted in shorter length of hospital stay (4.9 +/- 0.9 vs 9.6 +/- 1.8 days, P < 0.0001), lower incidence of ileus (7% vs 48%, P < 0.0001), and lower incidence of wound complications (2% vs 33%, P < 0.001) than the CST. Both techniques resulted in similar operative times, transfusion requirements, and mortality. Recurrences occurred in 7 per cent of patients at mean follow-up of 16 months in the CST group and 0 per cent at mean follow-up of 9 months after LR. The LR may have a short-term advantage over the CST in terms of incidence of ileus, wound complications, and hospital stay. Because of their unique advantage over traditional hernia repairs, both techniques may play a significant role in the future treatment of large ventral hernias. Adequate training will be essential for the safe and effective implementation of these techniques within the surgical community.

Early effects of Helicobacter pylori infection in patients undergoing bariatric surgery.

HYPOTHESIS: Following weight loss surgery, many patients initially experience nonspecific foregut symptoms. Helicobacter pylori infection of the gastric remnant may be associated with foregut symptoms. DESIGN: Inception cohort. SETTING: University hospital. PATIENTS: Ninety-nine consecutive patients being evaluated for weight loss surgery. INTERVENTION: All patients underwent preoperative esophagogastroduodenoscopy and H pylori testing. MAIN OUTCOME MEASURES: Foregut symptoms were documented at routine post-weight loss surgery follow-up visits. RESULTS: Preoperatively, 24% of patients tested positive for H pylori. Postoperative foregut symptoms were significant in 48% of the H pylori-positive group, and 19% of the H pylori-negative group (P = .02). This increase remained even after controlling for age, sex, preoperative presence of antritis, type of surgery performed, and body mass index (odds ratio, 3.6; 95% confidence interval,1.1-11.8). Patients with prolonged symptoms who tested positive for H pylori were given an eradication treatment. CONCLUSIONS: The prevalence of H pylori infection in patients undergoing weight loss surgery is high, and a significant proportion of them have postoperative foregut symptoms. Consideration should be given to H pylori treatment in these patients.

The effects of gastric surgery on systemic ghrelin levels in the morbidly obese.

HYPOTHESIS: Circulating ghrelin, produced primarily in the stomach, is a powerful orexigen. Ghrelin levels are elevated in states of hunger, but rapidly decline postprandially. Early alterations in ghrelin levels in morbidly obese patients undergoing weight reduction surgery may be attributed to gastric partitioning. DESIGN AND PATIENTS: Thirty-four patients underwent Roux-en-Y gastric bypass with a completely divided gastroplasty to create a 15-mL vertically oriented gastric pouch. Eight other patients underwent other gastric procedures that did not involve complete division of the stomach, including 4 vertical banded gastroplasties and 4 antireflux surgical procedures. Six additional patients undergoing antireflux surgery served as lean control subjects. Plasma samples were obtained before surgery and immediately after surgery. In a substudy, plasma was collected after Roux-en-Y limb formation and after dividing the stomach to identify any changes in plasma ghrelin levels. SETTING: Tertiary university medical center. MAIN OUTCOME MEASURES: Ghrelin levels at different stages of surgical intervention. RESULTS: Mean +/- SEM preoperative and postoperative ghrelin levels in the gastric bypass group were 355 +/- 20 and 246 +/- 13 pg/mL, respectively (P<.001). In the vertical banded gastroplasty group and in all patients undergoing antireflux surgery, ghrelin levels were not significantly changed. CONCLUSIONS: Compared with morbidly obese humans, lean controls had significantly higher plasma ghrelin levels at baseline. A divided gastroplasty creating a small proximal gastric pouch results in significant early declines in circulating ghrelin levels that are not observed with other gastric procedures. This may explain, in part, the loss of hunger sensation and rapid weight loss observed following gastric bypass surgery.

Disparity between symptomatic and physiologic outcomes following esophageal lengthening procedures for antireflux surgery.

Although esophageal lengthening procedures (Collis gastroplasty) have been recommended as an adjunct to antireflux surgery in patients with shortened esophagus, there are few data on physiologic outcomes in these patients. This study details the long-term outcomes in patients who underwent antireflux surgery with Collis gastroplasty. All patients undergoing esophagogastric fundoplication (EGF) with a Collis gastroplasty for the management of gastroesophageal reflux disease or paraesophageal hernia were identified from a prospectively maintained database. Symptom questionnaires were used during follow-up to assess symptomatic outcomes. Barium esophogram, upper endoscopy with biopsy, and catheterless esophageal acid monitoring (BRAVO system) were recommended for all patients. Patients with abnormal results of physiologic studies underwent further treatment based on a standardized algorithm. Between 1996 and 2002, a total of 68 patients underwent EGF with Collis gastroplasty. Twenty-seven (40%) had a large paraesophageal hernia, and 20 (30%) had undergone a prior EGF. Fifty-six (82%) of the procedures were performed laparoscopically. Mean follow-up time was 30 months, with 10 (15%) patients lost to latest follow-up. Symptomatic outcome data were available for 85% of patients, with significant improvements reported for heartburn (86%), chest pain (90%), dysphagia (89%), and regurgitation (91%). Most patients (84%) were off medications. Physiologic data were completed in 37% of the patients. Of those undergoing physiologic follow-up studies, 17% had recurrent hiatal hernia, and 80% had endoscopically identified esophagitis and pathologic esophageal acid exposure on pH testing. Despite this, 65% of the patients with objectively identified abnormalities reported significant symptomatic improvement compared to their preoperative symptoms. Two patients developed changes associated with Barrett's esophagus that were not present preoperatively. Distal esophageal injury can persist after EGF with Collis gastroplasty, despite significant symptomatic improvements. Appropriate follow-up in these patients requires objective surveillance, which should eventuate in further treatment if esophageal acid is not completely controlled. Although the Collis gastroplasty is conceptually appealing, these results call into question the liberal application of this technique during EGF.

Comparison of tissue integration between polyester and polypropylene prostheses in the preperitoneal space.

Tissue integration and implant characteristics of various biomaterials commonly used for inguinal hernia repair have not been studied extensively. The aim of this study is to compare behavior and tissue response between two new polyester prostheses and a commonly used polypropylene (PP) mesh. The polyester prostheses utilized were polyester flat (PF) and polyester soft three-dimensional (PS); the PP mesh utilized was Marlex. Eight randomly assigned 4 x 4-cm2 pieces of two different meshes were fixed in the preperitoneal space with a centrally placed single suture. Gross evaluation included shrinkage and stiffness. Histological evaluation included amount of fibrous and fat encapsulation, connective tissue, foreign-body reaction, neovascularization, hemorrhage, necrosis, and exudate. Evaluations were graded on a zero to four scale. The area and the area ratio were measured using a calibrated micrometer. PP mesh resulted in more fibrous encapsulation and stiffness than PF and PS prostheses. PP also resulted in less connective tissue formation and foreign-body reaction than PF and PS prostheses. There was no difference in fat encapsulation, necrosis, hemorrhage, or exudate between prostheses. Both polyester prostheses (PF and PS) have better tissue integration than the PP mesh, as evidenced by the higher amount of connective tissue and lower extent of fibrous encapsulation.

Does setting specific goals and providing feedback during training result in better acquisition of laparoscopic skills?

The aim of this study was to evaluate whether setting specific goals and providing feedback stimulates trainees to improve their laparoscopic skills. Two groups of eight fourth-year medical students practiced on a MIST-VR trainer, a black box laparoscopic suturing trainer, and computer-based training modules for 30 minutes, twice a week for 3 weeks. A precourse assessment of laparoscopic and open suturing skills and performance of MIST-VR tasks was obtained. Students in group A were given specific goals to achieve and were provided feedback. Group B was given no specific goals or feedback. At the end of the course, seven different tasks and skills were evaluated and subjectively scored during a laparoscopic cholecystectomy in an animal laboratory. A higher number of students in group A completed 10 or more repetitions in the MIST-VR than in group B. The groups showed no difference in final MIST-VR or overall scores in the animal laboratory. The only different scores between groups were for the use of the nondominant hand (NDH). The initial scores in the acquired cut task (ACT) in the MIST-VR correlated well with the performance in the animal laboratory. Setting goals and providing feedback tended to motivate students to practice more compared with the self-directed group. There was no difference in final MIST-VR scores or the performance in the animal laboratory, except for the NDH. The best predictor of performance was initial ACT score.

Laparoscopic versus open umbilical hernia repair.

BACKGROUND: The use of prosthetic material for open umbilical hernia repair has been reported to reduce recurrence rates. The aim of this study was to compare outcomes after laparoscopic versus open umbilical hernia repair. METHODS: We reviewed all umbilical hernia repairs performed from November 1995 to October 2000. Demographic data, hernia characteristics, and outcomes were compared. RESULTS: Of the 76 patients identified, 32 underwent laparoscopic repair (LR), 24 primary suture repairs (PSR), and 20 open repairs with mesh (ORWM). Preoperative characteristics were similar between groups. Hernia size was similar between LR and ORWM groups, and both were larger than that in the PSR group. ORWM compared with the other techniques resulted in longer operating time, more frequent use of drains, higher complication rates, and prolonged return to normal activities (RTNA). The length of stay (LOS) was longer in the ORWM than in the PSR group. When compared with ORWM, LR resulted in lower recurrence rates. LR resulted in fewer recurrences in patients with previous repairs and hernias larger than 3 cm than in both open techniques. CONCLUSIONS: LR results in faster RTNA, and lower complication and recurrence rates compared with those in ORWM. Patients with larger hernias and previous repairs benefit from LR.

Development and in vitro studies of a polyethylene terephthalate-gold nanoparticle scaffold for improved biocompatibility.

Polyethylene terephthalate (PET) mesh is one of the most commonly used synthetic biomaterials for tension-free hernia repair. In an effort to improve the biocompatibility of PET mesh, gold nanoparticles (AuNP) in various concentrations were conjugated to the PET surface to develop PET-AuNP scaffolds. These novel scaffolds were characterized with Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) to assess the addition of functional groups, presence of AuNPs, and thermal stability of the modified PET mesh, respectively. The biocompatibility of the PET-AuNP scaffolds was evaluated through in vitro cell culture assays. The cellularity of cells exposed to the PET-AuNP scaffolds, as well as the scaffolds' ability to reduce reactive oxygen species, was assessed using L929 murine fibroblasts. Antimicrobial properties of AuNPs conjugated to PET mesh were tested against the bacteria Pseudomonas aeruginosa. Results from the FT-IR showed presence of COOH groups while SEM displayed bonding of AuNPs to the PET surface. DSC results indicated that the PET more than likely did not undergo any detrimental degradation due to the surface modification. Results from the in vitro studies showed that AuNPs, in optimal concentrations (1× concentrations), enhanced cellularity, reduced ROS, and reduced bacteria adhesion to PET. These studies demonstrated enhanced biocompatibility of the AuNP conjugated PET mesh over pristine PET mesh.

Absorbable versus nonabsorbable mesh repair of congenital diaphragmatic hernias in a growing animal model.

INTRODUCTION: The repair of large congenital diaphragmatic hernia frequently results in patch disruption and recurrence as patients grow in size. Absorbable meshes allow for ingrowth of endogenous tissue as they are degraded, providing a more natural and durable repair. The aim of this study was to compare the characteristics of the new diaphragmatic tissue between an absorbable biologic mesh and a nonabsorbable mesh for repairing diaphragmatic hernia in a growing animal model. METHODS: The left hemi-diaphragm of twenty 2-month-old Yucatan pigs was nearly completely resected. Small intestinal submucosa (SIS; Cook Biotech, Lafayette, IN) and expanded polytetrafluoroethylene (ePTFE; W.L. Gore & Associates, Flagstaff, AZ) were randomly assigned to cover the defect in 10 animals each, and were survived for 6 months. During necropsy, newly formed diaphragmatic tissue was evaluated and compared between the two groups. RESULTS: At necropsy, the animals had tripled their weight. Patch disruption and herniation occurred in 3 animals in the ePTFE group and none in the SIS group. The SIS mesh had better integration to the chest wall (2.8 ± 0.2 versus 1.3 ± 0.3), more muscle growth within the newly formed diaphragmatic tissue (1.9 ± 0.2 versus 0.4 ± 0.2), and less fibrotic tissue (2.1 ± 0.5 versus 3.4 ± 0.4) than ePTFE. There was no difference between SIS and ePTFE in terms of adhesion scores to the lung (2 ± 0.4 versus 2.4 ± 0.4) and liver (1.8 ± 0.3 versus 2.2 ± 0.5). CONCLUSION: SIS allows for tissue ingrowth from surrounding tissue as it degrades, providing a more durable repair with 30% less incidence of herniation in a porcine model. As the diaphragm grows, SIS resulted in a more natural repair of the defect with more tissue growth, better tissue integration, and a comparable adhesion formation to ePTFE.

Characterization of bionanocomposite scaffolds comprised of amine-functionalized gold nanoparticles and silicon carbide nanowires crosslinked to an acellular porcine tendon.

As one of the most common proteins found in the human body, collagen is regarded as biocompatible and has many properties making it ideal for soft-tissue repair applications. However, collagen matrices fabricated from purified forms of collagen are notoriously weak and easily degraded by the body. The extracellular matrix of many tissues including human dermis, porcine dermis, and porcine small intestine submucosa are often utilized instead, and several of these scaffolds are crosslinked. Crosslinking has been shown to improve the mechanical properties of collagenous tissues and increase their resistance to degradation. In this study we investigated two novel "bionanocomposite" materials in which either gold nanoparticles or silicon carbide nanowires were crosslinked to a porcine tendon. Scanning electron micrographs confirmed that the nanomaterials were successfully crosslinked to the tissues. A collagenase assay, tensile testing, flow cytometry, and bioreactor studies were also performed to further characterize the properties of these novel materials. The results of these studies indicated that crosslinking porcine diaphragm tissues with nanomaterials resulted in scaffolds with improved resistance to enzymatic degradation and appropriate biocompatibility characteristics, thus warranting further study of these materials for soft tissue repair and tissue engineering applications.

Characterization of bionanocomposite scaffolds comprised of amine-functionalized single-walled carbon nanotubes crosslinked to an acellular porcine tendon.

Carbon nanotubes (CNT) possess many unique electrical and mechanical properties that make them useful for a variety of industrial and biomedical applications. They are especially attractive materials for biomedical applications since their dimensions are similar to components of the extracellular matrix. In this study, amine-functionalized single-walled carbon nanotubes were crosslinked to an acellular porcine diaphragm tendon. The resulting bionanocomposite scaffolds were subjected to a number of materials characterization techniques including a collagenase assay, uniaxial tensile testing, modulated differential scanning calorimetry, and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to determine whether the properties of the original extracellular matrix were altered by the treatment processes. A variety of SWCNT concentrations were investigated. While none of the conditions investigated resulted in bionanocomposites with significantly improved physicochemical properties, no detrimental effects were observed due to any of the processing steps. Future studies should be performed to determine if carbon nanotubes can influence cellular adhesion and function in order to promote rapid integration and remodeling.