Efficient Polymeric Nanoparticle Gene Delivery Enabled Via Tri- and Tetrafunctional Branching.

Poly(ß-amino ester) (PBAE) nanoparticles (NPs) show great promise for nonviral gene delivery. Recent studies suggest branched PBAEs (BPBAEs) offer advantages over linear counterparts, but the effect of polymer structure has not been well investigated across many chemical constituents. Here, a library of BPBAEs was synthesized with tri- and tetrafunctional branching. These polymers self-assemble with DNA to form highly cationic, monodisperse NPs with notably small size (∼50 nm). Optimal transfection occurred with polymer structures that featured moderate PBAE branching, enabling complete DNA encapsulation, rapid NP uptake, and robust expression at low DNA doses and polymer amounts. Optimized NPs enabled efficient DNA delivery to diverse cell types in vitro while maintaining high cellular viability, demonstrating significant improvements over a well-performing linear PBAE counterpart. BPBAEs also facilitated efficient mRNA and siRNA delivery, highlighting the versatility of these structures and demonstrating the broad utility of BPBAE NPs as vectors for nucleic acid delivery.

Fluorescein-conjugated hyaluronic acid enables visualization of retained ophthalmic viscosurgical device in anterior chamber.

PURPOSE: To develop and assess the utility of an ophthalmic viscosurgical device (OVD) manufactured with fluorescein-conjugated hyaluronic acid (conjHA). SETTING: Department of Biomedical Engineering and the Wilmer Eye Institute, Johns Hopkins University and School of Medicine, Baltimore, Maryland. DESIGN: Laboratory study. METHODS: ConjHA and unconjugated HA (unconjHA) at varied ratios were used to produce OVD (conjOVD) with varied fluorescence intensity. The conjHA:unconjHA ratio was optimized to maximize clarity under white light and fluorescence intensity under cobalt blue light (CBL), allowing for conditional visualization. The effect of conjugation on conjOVD viscosity was assessed by rotational rheometry. Intraocular lenses (IOLs) were immersed in conjOVD for 4 hours to assess staining of IOLs. A proof-of-concept study was performed in ex vivo porcine eyes. After injection and visualization, the OVDs were removed from the eyes by irrigation/aspiration (I/A). RESULTS: 0.5 mg/mL of conjHA (degree of substitution = 0.005) enabled robust fluorescence of conjOVD under CBL. Fluorescein conjugation did not significantly affect conjOVD viscosity ( P > .05 for mean difference in viscosity at all shear rates tested). No staining of IOLs was appreciated. ConjOVD was visualized under CBL when injected ex vivo and maintained clarity of the anterior chamber under white light. Importantly, conjHA enabled delineation of retained OVD after I/A. CONCLUSIONS: Use of OVD composed of fluorescein-conjugated HA is a feasible method to enable conditional visualization of OVD intraoperatively without nonspecific staining of ocular structures. Further development of this technology may enable accelerated OVD removal in ocular surgery or decreased OVD retention postoperatively.

Preprocedural Computed Tomography Planning for Surgical Aortic Valve Replacement.

BACKGROUND: Selection of transcatheter valve size using preprocedural computed tomography (CT) is standardized and well established. However, valve sizing for surgical aortic valve replacement (SAVR) is currently performed intraoperatively by using sizers, which may result in variation among operators and risk for prosthesis-patient mismatch. This study evaluated the usefulness of CT annulus measurement for SAVR valve sizing. METHODS: This study included patients who underwent SAVR using Inspiris or Magna Ease and received preoperative electrocardiogram-gated CT imaging. Starting from June 2022, study investigators applied a CT sizing algorithm using CT-derived annulus size to guide minimum SAVR label size. The final decision of valve selection was left to the operating surgeon during SAVR. The study compared the appropriateness of valve selection (comparing implanted size with CT-predicted size) and prosthesis-patient mismatch rates without aortic root enlargement between 2 cohorts: 102 cases since June 2022 (CT sizing cohort) and 180 cases from 2020 to 2021 (conventional sizing cohort). RESULTS: Implanted size smaller than CT predicted size and severe prosthesis-patient mismatch were significantly lower by CT sizing than by conventional sizing (12% vs 31% [P = .001] and 0% vs 6% [P = .039], respectively). Interoperator variability was a factor associated with implanted size smaller than CT predicted with conventional sizing, whereas it became nonsignificant with CT sizing. CONCLUSIONS: Applying CT sizing to SAVR led to improved valve size selection, less prosthesis-patient mismatch, and less interoperator variability. CT sizing for SAVR could also be used to predict prosthesis-patient mismatch before SAVR and identify patients who need aortic root enlargement.

Intraocular Lens Unfurling Time Exponentially Decays with Increased Solution Temperature.

Purpose: Intraocular lens (IOL) unfurling can be a rate-limiting step in cataract surgery, limiting operative efficiency. Furthermore, inefficient unfurling has important implications for clinical outcomes. We examine the effects of solution temperature on IOL unfurling time using three in vitro models of the ocular environment. Methods: IOLs were injected into a 6-well plate filled with balanced salt solution (BSS), dispersive ophthalmic viscoelastic device (OVD), or cohesive OVD. Experiments were also performed in a plastic eye filled with dispersive or cohesive OVD. IOL unfurling time was recorded against the temperature of the respective solution. Results: IOL unfurling time decayed exponentially as solution temperature increased in all experiments, including the BSS-filled 6-well plate, the OVD-filled 6-well plate, and the OVD-filled plastic eye. IOLs failed to unfurl within 10 min at 10°C, below the glass transition temperature of the tested IOLs. Increasing solution temperature from 20°C to 30°C decreases IOL unfurling by greater than 2 min. Further heating to 40°C did not significantly decrease IOL unfurling time. Conclusion: Increased solution temperature rapidly decreases IOL unfurling time in vitro. IOLs do not unfurl within a clinically acceptable timeframe at or below their glass transition temperature. Increased BSS and/or OVD temperature may be a potential method to decrease IOL unfurling time in cataract surgery. However, future research is needed to elucidate potential consequences of warmed BSS and/or OVD on post-operative outcomes. This study demonstrates the potential for temperature regulation to decrease cataract surgery operative time and provides preliminary evidence to justify future clinical validation of this relationship.

During cataract surgery, a prosthetic intraocular lens (IOL) is inserted into the eye once the clouded lens is removed. The IOL must then unfurl before the procedure can proceed. When IOLs fail to unfurl or unfurl slowly, this can delay the operation and may even cause post-operative complications. Thus, we studied the effect temperature may have on IOL unfurling time to optimize this segment of the operation. We injected IOLs into solutions of saline (balanced salt solution) or ophthalmic viscoelastic device (OVD), two fluids injected into the eye during surgery. In both a well plate and a plastic eye, we found that increasing the temperature of the solution significantly affected IOL unfurling time. Specifically, heating the solution from refrigeration to room temperature decreased unfurling time from over 10 min to less than four. Heating to physiological temperature further decreased unfurling time to less than a minute. Our results show promise for potentially utilizing heated BSS and/or OVD to accelerate IOL unfurling and decrease cataract surgery operative time.