Effect of Cross-Linkers on Mussel- and Elastin-Inspired Adhesives on Physiological Substrates.

Surgical adhesives can be useful in wound closure because they reduce the risk of infection and pain associated with sutures and staples. However, there are no commercially available surgical adhesives for soft tissue wound closure. To be effective, soft tissue adhesives must be soft and flexible, strongly cohesive and adhesive, biocompatible, and effective in a moist environment. To address these criteria, we draw inspiration from the elasticity and resilience of elastin proteins and the adhesive of marine mussels. We used an elastin-like polypeptide (ELP) for the backbone of our adhesive material due to its elasticity and biocompatibility. A mussel-inspired adhesive molecule, l-3,4-dihydroxyphenylalanine (DOPA), was incorporated into the adhesive to confer wet-setting adhesion. In this study, an ELP named YKV was designed to include tyrosine residues and lysine residues, which contain amine groups. A modified version of YKV, named mYKV, was created through enzymatic conversion of tyrosine residues into DOPA. The ELPs were combined with iron(III) nitrate, sodium periodate, and/or tris(hydroxymethyl)phosphine (THP) cross-linkers to investigate the effect of DOPA- and amine-based cross-linking on adhesion strength and cure time on porcine skin in a warm, humid environment. Incorporation of DOPA into the ELP increased adhesive strength by 2.5 times and reduced failure rates. Iron cross-linkers improved adhesion in the presence of DOPA. THP increased adhesion for all proteins tested even in the absence of DOPA. Using multiple cross-linkers in a single formulation did not significantly improve adhesion. The adhesives with the highest performance (iron nitrate mixed with mYKV and THP mixed with YKV or mYKV) on porcine skin had 10-18 times higher adhesion than a commercial sealant and reached appreciable adhesive strength within 10 min.

Postoperative hemorrhage after biomedical glue sling technique in microvascular decompression for vertebrobasilar artery-associated cranial nerve diseases: A retrospective study of 14 cases.

Background: The biomedical glue sling technique is a convenient and effective method for vertebrobasilar artery-associated cranial nerve diseases but postoperative hemorrhage is poorly understood. Methods: We retrospectively reviewed 14 of 1157 patients associated with cranial nerve diseases who were subjected to the biomedical glue sling technique in microvascular decompression at our hospital from January 2015 to January 2020. Results: There were 14 patients with cranial nerve diseases included in this study. A clinical diagnosis of postoperative hemorrhage was made after an average of 41.75 h (ranging between 0.5 and 95 h). A cerebellopontine angle hemorrhage was presented in 5 patients, while basal ganglia hemorrhage was observed in 2 patients. Both a cerebellopontine angle and brainstem hemorrhage was seen in 1 patient. Distal supratentorial subdural hemorrhage was recorded in 6 patients. The correlation coefficient was -0.1601 (p = 0.7094) between the standard deviation of systolic blood pressure and the Hemphill Score, -0.2422 (p = 0.5633) between the coefficient of variation of systolic blood pressure and the Hemphill Score, and -0.0272 (p = 0.9489) between the range of systolic blood pressure and the Hemphill Score. Conclusions: The incidence of postoperative hemorrhage after MVD with the biomedical glue sling technique is higher than with traditional MVD and most cases have a favorable prognosis. Postoperative symptoms are the main area of concern and changes in symptoms usually suggest the occurrence of hemorrhage. Several factors, including surgical procedures, the release of CSF, and blood pressure might be associated with hemorrhaging. We still believe such a technique is an efficient approach to treating complicated cranial nerve diseases.

Biomedical Glue Sling Technique in Microvascular Decompression for Trigeminal Neuralgia Caused by Atherosclerotic Vertebrobasilar Artery: A Description of Operative Technique and Clinical Outcomes.

BACKGROUND: Microvascular decompression (MVD) is the most definitive surgical treatment for trigeminal neuralgia (TN). In the case in which an atherosclerotic vertebrobasilar artery (aVBA) offends the trigeminal nerve, the postoperative outcomes have been reported to be less satisfactory in terms of symptom recurrence and complications. In this study, the authors present their experience using a biomedical sling for MVD in patients with aVBA-associated TN. METHODS: A retrospective study of 22 consecutive patients who underwent the biomedical glue sling technique in MVD for TN with aVBA was conducted between September 2016 and June 2017. RESULTS: Intraoperatively, aVBA was regarded as the direct or indirect offending vessel in 22 patients. In addition to aVBA, other vessels involved in neurovascular conflict included superior cerebellar artery in 12 patients, veins in 1, and anterior inferior cerebellar artery in 6. All 22 patients underwent the biomedical glue sling technique. Postoperatively, TN was completely resolved in 20 (91%) patients and partially relieved in 2 (9%) patients. During the follow-up period of 18-27 months, pain developed severely in those 2 patients but could be relieved with carbamazepine. As for complications, postoperative hypoacusia occurred immediately in 1 case, with complete resolution in 2 months. CONCLUSIONS: The biggest advantage of the biomedical glue sling technique is its simplicity in achieving complete decompression, requiring relatively less space and time. Because the outcome of traditional MVD regarding aVBA-associated TN remains controversial, the biomedical glue sling technique in MVD provides an alternative decompressive method for patients with TN associated with aVBA. However, further studies with a larger series and control group are required to prove the high effectiveness of this method.

Microvascular Decompression for Hemifacial Spasm Associated with Vertebral Artery: Biomedical Glue-Coated Teflon Sling Transposition Technique.

BACKGROUND: Microvascular decompression is the most effective treatment for hemifacial spasm. However, when encountering hemifacial spasm associated with vertebral artery (VA), the procedure is more challenging and requires complicated operation techniques. The authors retrospectively analyzed the clinical characteristics of this group of cases and investigated reasonable transposition procedures for different anatomic classifications. METHODS: We retrospectively analyzed 117 cases that underwent their first microvascular decompression for hemifacial spasm between June 2010 and December 2016, which had all associated with vertebral artery compression diagnosed by preoperational radiology examination. The study first classified offending vessels into 3 types according to operative anatomy and designed personalized decompression management according to different forms of neurovascular conflict. Curative effects and complications were assessed. RESULTS: The offending vessels were artificially divided into 3 types according to both arterial pattern and compression direction: 1) ipsilateral VA plus anterior inferior cerebellar artery compressing the facial nerve from the ventrolateral direction in 72 (61.5%) cases; 2) ipsilateral VA plus posterior inferior cerebellar artery compressing the facial nerve from the caudal-medial direction in 31 (26.5%) cases; 3) bilateral VA compressing the facial nerve in 14 (12.0%) cases. We selected corridors to expose the neurovascular conflict site between the suprafloccular-transhorizontal fissure approach and subtonsillar-transcerebellomedullary fissure approach. The methods of decompression consist of anteromedial and posterolateral transposition by using biomedical glue-coated Teflon sling. Sufficient decompression of the offending vessels was safely performed in all cases. All cases had total relief of symptoms immediately after their operations. Follow-up periods ranged from 16-90 months, and total recovery occurred in 110 cases (94.0%). In 7 cases (6.0%), 90% recovery occurred. CONCLUSIONS: Accuracy and comprehensive recognition of anatomic features of the offending vessels are crucial for the management of hemifacial spasm associated with vertebral artery compression. Appropriate approaches combined with the biomedical glue-coated Teflon sling transposition technique can allow adequate mobilization of the vertebral artery and bring complete postoperative symptom relief for most cases.

A bioinspired elastin-based protein for a cytocompatible underwater adhesive.

The development of adhesives that can be applied and create strong bonds underwater is a significant challenge for materials engineering. When the adhesive is intended for biomedical applications, further criteria, such as biocompatibility, must be met. Current biomedical adhesive technologies do not meet these needs. In response, we designed a bioinspired protein system that shows promise to achieve biocompatible underwater adhesion coupled with environmentally responsive behavior that is "smart" - that is, it can be tuned to suit a specific application. The material, ELY16, is constructed from an elastin-like polypeptide (ELP) that can be produced in high yields from Escherichia coli and can coacervate in response to environmental factors such as temperature, pH, and salinity. To confer wet adhesion, we utilized design principles from marine organisms such as mussels and sandcastle worms. When expressed, ELY16 is rich in tyrosine. Upon modification with the tyrosinase enzyme to form mELY16, the tyrosine residues are converted to 3,4-dihydroxyphenylalanine (DOPA). Both ELY16 and mELY16 exhibit cytocompatibility and significant dry adhesion strength (>2 MPa). Modification with DOPA increases protein adsorption to glass and provides moderate adhesion strength (∼240 kPa) in a highly humid environment. Furthermore, this ELP exhibits a tunable phase transition behavior that can be formulated to coacervate in physiological conditions and provides a convenient mechanism for application underwater. Finally, mELY16 possesses significantly higher adhesion strength in dry, humid, and underwater environments compared with a commercially available fibrin sealant. To our knowledge, mELY16 provides the strongest bonds of any rationally designed protein when used completely underwater, and its high yields make it more viable for commercial application compared to natural adhesive proteins. In conclusion, this ELP shows great potential to be a new "smart" underwater adhesive.

Repair of bad eyebrow and blepharotosis by a new eyebrow excision method with biomedical glue / 重庆医科大学学报

Objective:To improve the shape of bad eyebrow and the appearance by eyebrow skin relaxation and blepharotosis,a new method be used to binding the incision with biomedical glue after eyebrow excision operation.Methods:For those bad or ptotic eyebrows and severe blepharotosis patients,the bad eyebrows and the additional skin of upper eyelid was removed first,then the loosend orbicularis muscle was suspended according to the different situations.Absorption suture be used in series intradermally,then biomedical glue be used to link the incision.After that a new eyebrow been painted to cover the incision immediately.Results:106 cases were carried out the above operations,the shape of bad eyebrows and the appearance of eyebrow relaxation and blepharotosis were repaired completely.After operation the patient's life were not be interrupted.They can shampoo and face-wash as one's pleases.No one can find the change after operation easily.Conclusion:The bad eyebrows and the aged look of orbicularis area could be improved significantly by this operation.The use of biomedical glue can make the operation's influence to minimum and the patients accepted this operation easily.