High-throughput fabrication of antimicrobial phage microgels and example applications in food decontamination.

Engineered by nature, biological entities are exceptional building blocks for biomaterials. These entities can impart enhanced functionalities on the final material that are otherwise unattainable. However, preserving the bioactive functionalities of these building blocks during the material fabrication process remains a challenge. We describe a high-throughput protocol for the bottom-up self-assembly of highly concentrated phages into microgels while preserving and amplifying their inherent antimicrobial activity and biofunctionality. Each microgel is comprised of half a million cross-linked phages as the sole structural component, self-organized in aligned bundles. We discuss common pitfalls in the preparation procedure and describe optimization processes to ensure the preservation of the biofunctionality of the phage building blocks. This protocol enables the production of an antimicrobial spray containing the manufactured phage microgels, loaded with potent virulent phages that effectively reduced high loads of multidrug-resistant Escherichia coli O157:H7 on red meat and fresh produce. Compared with other microgel preparation methods, our protocol is particularly well suited to biological materials because it is free of organic solvents and heat. Bench-scale preparation of base materials, namely microporous films (the template for casting microgels) and pure concentrated phage suspension, requires 3.5 h and 5 d, respectively. A single production run, that yields over 1,750,000 microgels, ranges from 2 h to 2 d depending on the rate of cross-linking chemistry. We expect that this platform will address bottlenecks associated with shelf-stability, preservation and delivery of phage for antimicrobial applications, expanding the use of phage for prevention and control of bacterial infections and contaminants.

Corticosteroids for managing acute pain subsequent to surgical extraction of mandibular third molars: A systematic review and meta-analysis.

BACKGROUND: Corticosteroids are used to manage pain after surgical tooth extractions. The authors assessed the effect of corticosteroids on acute postoperative pain in patients undergoing surgical tooth extractions of mandibular third molars. TYPES OF STUDIES REVIEWED: The authors conducted a systematic review and meta-analysis. The authors searched the Epistemonikos database, including MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and the US clinical trials registry (ClinicalTrials.gov) from inception until April 2023. Pairs of reviewers independently screened titles and abstracts, then full texts of trials were identified as potentially eligible. After duplicate data abstraction, the authors conducted random-effects meta-analyses. Risk of bias was assessed using Version 2 of the Cochrane Risk of Bias tool and certainty of the evidence was determined using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: Forty randomized controlled trials proved eligible. The evidence suggested that corticosteroids compared with a placebo provided a trivial reduction in pain intensity measured 6 hours (mean difference, 8.79 points lower; 95% CI, 14.8 to 2.77 points lower; low certainty) and 24 hours after surgical tooth extraction (mean difference, 8.89 points lower; 95% CI, 10.71 to 7.06 points lower; very low certainty). The authors found no important difference between corticosteroids and a placebo with regard to incidence of postoperative infection (risk difference, 0%; 95% CI, -1% to 1%; low certainty) and alveolar osteitis (risk difference, 0%; 95% CI, -3% to 4%; very low certainty). PRACTICAL IMPLICATIONS: Low and very low certainty evidence suggests that there is a trivial difference regarding postoperative pain intensity and adverse effects of corticosteroids administered orally, submucosally, or intramuscularly compared with a placebo in patients undergoing third-molar extractions.

Analgesics for the management of acute dental pain in the pediatric population: A systematic review and meta-analysis.

BACKGROUND: The authors assessed the clinical effectiveness of analgesics to manage acute pain after dental extractions and pain associated with irreversible pulpitis in children. TYPES OF STUDIES REVIEWED: The authors searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and US Clinical Trials registry from inception through November 2020. They included randomized controlled trials comparing any pharmacologic interventions with each other and a placebo in pediatric participants undergoing dental extractions or experiencing irreversible pulpitis. After duplicate screening and data abstraction, the authors conducted random-effects meta-analyses. They assessed risk of bias using the Cochrane Risk of Bias 2.0 tool and certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: The authors included 6 randomized controlled trials reporting 8 comparisons. Ibuprofen may reduce pain intensity compared with acetaminophen (mean difference [MD], 0.27 points; 95% CI, -0.13 to 0.68; low certainty) and a placebo (MD, -0.19 points; 95% CI, -0.58 to 0.21; low certainty). Acetaminophen may reduce pain intensity compared with a placebo (MD, -0.13 points; 95% CI, -0.52 to 0.26; low certainty). Acetaminophen and ibuprofen combined probably reduce pain intensity compared with acetaminophen alone (MD, -0.75 points; 95% CI, -1.22 to -0.27; moderate certainty) and ibuprofen alone (MD, -0.01 points; 95% CI, -0.53 to 0.51; moderate certainty). There was very low certainty evidence regarding adverse effects. PRACTICAL IMPLICATIONS: Several pharmacologic interventions alone or in combination may provide a beneficial effect when managing acute dental pain in children. There is a paucity of evidence regarding the use of analgesics to manage irreversible pulpitis.

Injectable and topical local anesthetics for acute dental pain: 2 systematic reviews.

BACKGROUND: Local anesthesia is essential for pain control in dentistry. The authors assessed the comparative effect of local anesthetics on acute dental pain after tooth extraction and in patients with symptomatic irreversible pulpitis. TYPES OF STUDIES REVIEWED: The authors searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and the US Clinical Trials registry through November 21, 2020. The authors included randomized controlled trials (RCTs) comparing long- vs short-acting injectable anesthetics to reduce pain after tooth extraction (systematic review 1) and evaluated the effect of topical anesthetics in patients with symptomatic pulpitis (systematic review 2). Pairs of reviewers screened articles, abstracted data, and assessed risk of bias using a modified version of the Cochrane risk of bias 2.0 tool. The authors assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: Fourteen RCTs comparing long- vs short-acting local anesthetics suggest that bupivacaine may decrease the use of rescue analgesia and may not result in additional adverse effects (low certainty evidence). Bupivacaine probably reduces the amount of analgesic consumption compared with lidocaine with epinephrine (mean difference, -1.91 doses; 95% CI, -3.35 to -0.46; moderate certainty) and mepivacaine (mean difference, -1.58 doses; 95% CI, -2.21 to -0.95; moderate certainty). Five RCTs suggest that both benzocaine 10% and 20% may increase the number of people experiencing pain reduction compared with placebo when managing acute irreversible pulpitis (low certainty). PRACTICAL IMPLICATIONS: Bupivacaine may be superior to lidocaine with epinephrine and mepivacaine with regard to time to and amount of analgesic consumption. Benzocaine may be superior to placebo in reducing pain for 20 through 30 minutes after application.

Self-assembling nanofibrous bacteriophage microgels as sprayable antimicrobials targeting multidrug-resistant bacteria.

Nanofilamentous bacteriophages (bacterial viruses) are biofunctional, self-propagating, and monodisperse natural building blocks for virus-built materials. Minifying phage-built materials to microscale offers the promise of expanding the range function for these biomaterials to sprays and colloidal bioassays/biosensors. Here, we crosslink half a million self-organized phages as the sole structural component to construct each soft microgel. Through an in-house developed, biologics-friendly, high-throughput template method, over 35,000 phage-built microgels are produced from every square centimetre of a peelable microporous film template, constituting a 13-billion phage community. The phage-exclusive microgels exhibit a self-organized, highly-aligned nanofibrous texture and tunable auto-fluorescence. Further preservation of antimicrobial activity was achieved by making hybrid protein-phage microgels. When loaded with potent virulent phages, these microgels effectively reduce heavy loads of multidrug-resistant Escherichia coli O157:H7 on food products, leading to up to 6 logs reduction in 9 hours and rendering food contaminant free.

Inducing Microscale Structural Order in Phage Nanofilament Hydrogels with Globular Proteins.

Biological hydrogels play important physiological roles in the body. These hydrogels often contain ordered subdomains that provide mechanical toughness and other tissue-specific functionality. Filamentous bacteriophages are nanofilaments with a high aspect ratio that can self-assemble into liquid crystalline domains that could be designed to mimic ordered biological hydrogels and can thus find applications in biomedical engineering. We have previously reported hydrogels of pure cross-linked liquid crystalline filamentous phage formed at very high concentrations exhibiting a tightly packed microstructure and high stiffness. In this work, we report a method for inducing self-assembly of filamentous phage into liquid crystalline hydrogels at concentrations that are several orders of magnitude below that of lyotropic liquid crystal formation, thus creating structural order but a less densely packed microstructure. Hybrid hydrogels of M13 phage and bovine serum albumin (0.25 w/v%) were formed and shown to adsorb up to 16× their weight in water. Neither component gelled on its own at the low concentrations used, suggesting synergistic action between the two components in the formation of the hydrogel. The hybrid hydrogels exhibited repetitive self-healing under physiological conditions and at room temperature, autofluorescence in three channels, and antibacterial activity toward Escherichia coli host cells. Furthermore, the hybrid hydrogels exhibited a more than 2× higher ability to pack water compared to BSA-only hydrogels and 2× lower compression modulus compared to tightly packed M13-only hydrogels, suggesting that our method could be used to create hydrogels with tunable mechanical properties and pore structure through the addition of globular proteins, while maintaining bioactivity and microscale structural order.

Bacteria repellent protein hydrogel decorated with tunable, isotropic, nano-on-micro hierarchical microbump array.

We report the development of ordered shape-controllable microbump structures on protein hydrogels using polystyrene honeycomb templates. Addition of protein nanogels results in the formation of hierarchical nano-on-micro structures and increases surface hydrophilicity by over 55%, exhibiting bacteria repellency 100 times stronger than a flat hydrogel surface composed of the same protein.