Management of Cochlear Implant Electrode Arrays Misplaced in the Internal Auditory Canal: A Systematic Review.

OBJECTIVE: Misplacement of electrode arrays in the internal auditory canal (IAC) presents a unique clinical challenge. Speech recognition is limited for cochlear implant (CI) users with misplaced arrays, and there are risks with revision surgery including facial and/or cochlear nerve injury. DATABASES REVIEWED: PubMed, Embase, and Scopus. METHODS: A literature search was performed from inception to September 2023. The search terms were designed to capture articles on misplaced arrays and the management options. Articles written in English that described cases of array misplacement into the IAC for children and adults were included. The level of evidence was assessed using Oxford Center for Evidence Based Medicine guidelines. Descriptive statistical analyses were performed. RESULTS: Twenty-eight cases of arrays misplaced in the IAC were identified. Thirteen (46%) were patients with incomplete partition type 3 (IP3), and 7 (25%) were patients with common cavity (CC) malformations. Most misplaced arrays were identified postoperatively (19 cases; 68%). Of these cases, 11 (58%) were managed with array removal. No facial nerve injuries were reported with revision surgery. Eight cases (42%) were left in place. Several underwent mapping procedures in an attempt improve the sound quality with the CI. CONCLUSION: Electrode array misplacement in the IAC is a rare complication that reportedly occurs predominately in cases with IP3 and CC malformations. Removal of misplaced arrays from the IAC reportedly has not been associated with facial nerve injuries. Cases identified with IAC misplacement postoperatively can potentially be managed with modified mapping techniques before proceeding with revision surgery.

A Reproducible Peritonsillar Abscess Incision and Drainage Model for Junior Trainees.

OBJECTIVES: To describe the design and construction of a reproducible, low-cost, peritonsillar abscess (PTA) incision and drainage simulator and assess its impact on trainees' confidence. METHODS: The 2-part simulator we developed consisted of a manikin head with a fixed, partially open mouth and a modular PTA mold. The mold is created by injecting a lotion and water mixture into plastic bubbles, followed by silicone solidification. Neodymium magnets secure the silicone-abscess packet to the manikin's palate. The simulator was utilized during an academic otolaryngology residency training program Annual Otolaryngology Boot Camp. A self-assessment Likert scale questionnaire was used to evaluate participants' confidence before and after simulator training. Fourth-year medical students and junior (first and second year) residents who participated in the boot camp and agreed to complete the evaluation were included. RESULTS: Three medical students, 17 PGY-1, and 10 PGY-2 residents agreed to complete the evaluation. All trainees agreed the model was useful for learning skills. The overall post-training confidence Likert scores of participants, and PGY-1 residents in particular, significantly improved compared to their pre-training scores (P < .001). CONCLUSIONS: Our model offers an affordable and efficient training opportunity for residents to enhance their competence in managing PTAs. This approach, with its simple yet effective design and low production cost, shows potential for scalability on a broader scale.

Bell's Palsy and COVID-19: Insights from a Population-Based Analysis.

Background: Coronavirus disease 2019 (COVID-19) has been linked to Bell's palsy and facial paralysis. Studies have also shown increased risk of Bell's palsy in unvaccinated COVID-19 patients. Objective: To compare the relationship between Bell's palsy and COVID-19 infection and vaccination. Design: This is a retrospective longitudinal study. Methods: The COVID-19 research network was used to identify patients with facial palsy presenting to 70 health care organizations in the United States. The incidence of Bell's palsy was measured within an 8-week window after COVID-19 test or vaccination event in identified patients. Results: Incidence of facial palsy diagnosis (0.99%) was higher than the background rate within 2 months of COVID-19 infection. When compared with their negative counterparts, patients with COVID-19 infection had significantly higher risk of Bell's palsy (risk ratio [RR] = 1.77, p < 0.01) and facial weakness (RR = 2.28, p < 0.01). Risk ratio was also amplified when evaluating Bell's palsy (RR = 12.57, p < 0.01) and facial palsy (RR = 44.43; p < 0.01) in COVID-19-infected patients against patients who received COVID-19 vaccination. Conclusion: In our patient population, there is a higher risk of developing facial palsy within 2 months of COVID-19 infection versus vaccination. Vaccinated patients are not at higher risk of developing facial palsy.

A Systematic Review of Peritonsillar Abscess Simulators: Enhancing Training and Identifying the Need for Standardization.

OBJECTIVES: To systematically review the literature regarding previously described peritonsillar abscess (PTA) drainage simulation. DATA SOURCES: PubMed, Scopus, Web of Science, Ovid, and Cochrane. REVIEW METHODS: A search of the abovementioned databases was performed in August 2022 using the terms "peritonsillar abscess/quinsy," "incision/drainage/aspiration," and "simulation." No time restrictions were applied. We included studies that clearly described how their PTA models were built and underwent validation from experts and/or evaluation from trainees. Articles describing a model only without any evaluation and reports in languages other than English were excluded. RESULTS: Our search initially yielded 80 articles after duplicate removal, 10 of which met our criteria and were included. Two studies trained participants on both needle aspiration and incision and drainage (I&D), four studies on I&D only, and four on needle aspiration only. 87.5% to 100% of junior residents reported minimal exposure to PTA prior to simulation. Five studies provided some form of validation to their models. The value of the simulators to train participants on skills received better appreciation than their anatomical fidelity. The perceived confidence level of trainees in managing PTA, which was assessed in 7 studies, substantially improved after training. CONCLUSION: PTA simulation improves the confidence of trainees to perform PTA drainage. There is, however, a lack of standardization and evidence regarding transfer validity among PTA simulators. The development of a standardized PTA simulator could allow for more widespread use and increase resident comfort with this procedure in a pre-clinical setting. LEVEL OF EVIDENCE: NA Laryngoscope, 2023.

A case report of uremic tumoral calcinosis in the head and neck and literature review of calcified lesions of the head and neck.

Soft-tissue calcifications in the head and neck are relatively common and are the result of a wide variety of benign and malignant pathologies. They can present a diagnostic challenge given the broad range of underlying etiologies. Uremic tumoral calcinosis (UTC) is a rare complication of end-stage renal disease (ESRD) resulting from metastatic soft tissue calcification. Common sites include periarticular soft tissues of the shoulders, elbows, and hands (Pan and Chen, 2016). UTC can also affect the cervical spine and mimic osteosarcomas (Zhou et al., 2018). We present the case of a 71-year-old female with hypertension, left carotid artery stenosis, mitral valve prolapse, and ESRD secondary to diabetes mellitus type II (DMII) on peritoneal dialysis who was found to have large, heterogeneous, bilateral calcified neck masses. Given her clinical history, laboratory results, and imaging findings, she was diagnosed with UTC. In addition to this case, we provide an overview of tumoral calcinosis (TC) and a differential diagnosis for calcified lesions of the head and neck.

QCM-D Investigations on Cholesterol-DNA Tethering of Liposomes to Microbubbles for Therapy.

Lipid-shelled microbubbles (MBs) offer potential as theranostic agents, capable of providing both contrast enhancement in ultrasound imaging as well as a route for triggered drug release and improved localized drug delivery. A common motif in the design of such therapeutic vehicles is the attachment of the drug carrier, often in the form of liposomes, to the microbubble. Traditionally, such attachments have been based around biotin-streptavidin and maleimide-PDP chemistries. Comparatively, the use of DNA-lipid tethers offers potential advantage. First, their specificity permits the construction of more complex architectures that might include bespoke combinations of different drug-loaded liposomes and/or targeting groups, such as affimers or antibodies. Second, the use of dual-lipid tether strategies should increase the strength of the individual tethers tethering the liposomes to the bubbles. The ability of cholesterol-DNA (cDNA) tethers for conjugation of liposomes to supported lipid bilayers has previously been demonstrated. For in vivo applications, bubbles and liposomes often contain a proportion of polyethylene glycol (PEG) to promote stealth-like properties and increase lifetimes. However, the associated steric effects may hinder tethering of the drug payload. We show that while the presence of PEG reduced the tethering affinity, cDNA can still be used for the attachment of liposomes to a supported lipid bilayer (SLB) as measured via QCM-D. Importantly, we show, for the first time, that QCM-D can be used to study the tethering of microbubbles to SLBs using cDNA, signified by a decrease in the magnitude of the frequency shift compared to liposomes alone due to the reduced density of the MBs. We then replicate this tethering interaction in the bulk and observe attachment of liposomes to the shell of a central MB and hence formation of a model therapeutic microbubble.

Temporal Bone Resection for Squamous Cell Carcinoma of the Lateral Skull Base: Systematic Review and Meta-analysis.

OBJECTIVE: Temporal bone squamous cell carcinoma (TBSCC) is rare and often confers a poor prognosis. The aim of this study was to synthesize survival and recurrence outcomes data reported in the literature for patients who underwent temporal bone resection (TBR) for curative management of TBSCC. We considered TBSCC listed as originating from multiple subsites, including the external ear, parotid, and external auditory canal (EAC), or nonspecifically from the temporal bone. DATA SOURCES: PubMed, Cochrane Library, Embase, and manual search of bibliographies. REVIEW METHOD: A systematic literature review conducted in December 2020 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: Survival data were collected from 51 retrospective studies, resulting in a pooled cohort of 501 patients with TBSCC. Compared to patients undergoing lateral TBR (LTBR), patients undergoing subtotal (SBTR) or total (TTBR) TBR exhibited significantly higher rates of stage IV disease (P < .001), positive surgical margins (P < .001), facial nerve involvement (P < .001), and recurrent disease (P < .001). A meta-analysis of 15 studies revealed a statistically significant 97% increase in mortality in patients who underwent STBR or TTBR. On multivariate analysis, recurrent disease was independently associated with worse overall survival (P < .001). On univariate analysis, facial nerve involvement was also associated with decreased overall survival (P < .001). CONCLUSION: Recurrent disease was associated with risk of death in patients undergoing TBR. Larger prospective multi-institutional studies are needed to ascertain prognostic factors for a wider array of postoperative outcomes, including histology-specific survival and recurrence outcomes.

Horizon: Microfluidic platform for the production of therapeutic microbubbles and nanobubbles.

Microbubbles (MBs) have a multitude of applications including as contrast agents in ultrasound imaging and as therapeutic drug delivery vehicles, with further scope for combining their diagnostic and therapeutic properties (known as theranostics). MBs used clinically are commonly made by mechanical agitation or sonication methods, which offer little control over population size and dispersity. Furthermore, clinically used MBs are yet to be used therapeutically and further research is needed to develop these theranostic agents. In this paper, we present our MB production instrument "Horizon," which is a robust, portable, and user-friendly instrument, integrating the key components for producing MBs using microfluidic flow-focusing devices. In addition, we present the system design and specifications of Horizon and the optimized protocols that have so far been used to produce MBs with specific properties. These include MBs with tailored size and low dispersity (monodisperse); MBs with a diameter of ∼2 µm, which are more disperse but also produced in higher concentration; nanobubbles with diameters of 100-600 nm; and therapeutic MBs with drug payloads for targeted delivery. Multiplexed chips were able to improve production rates up to 16-fold while maintaining production stability. This work shows that Horizon is a versatile instrument with potential for mass production and use across many research facilities, which could begin to bridge the gap between therapeutic MB research and clinical use.

Granulomatosis with Polyangiitis as a Cause of Sudden-Onset Bilateral Sensorineural Hearing Loss: Case Report and Recommendations for Initial Assessment.

Granulomatosis with polyangiitis (GPA) is a severe systemic vasculitis that commonly affects the paranasal sinuses, upper and lower respiratory tracts, and kidneys. GPA has also been associated with sensorineural hearing loss (SNHL), through inflammation of the cochlear apparatus. Early recognition, diagnostic laboratory evaluation, and appropriate treatment are essential to improve outcomes and achieve remission for patients with GPA. Here, we present a case of bilateral sudden sensorineural hearing loss (SSNHL) and distal symmetric polyneuropathy as the first presenting signs of GPA. A specific diagnostic work-up to rule out autoimmune inner-ear disease in patients with bilateral SSNHL is not clearly stated in the clinical practice guidelines from the American Academy of Otolaryngology-Head and Neck Surgery. The aim of this paper is to delineate an appropriate diagnostic work-up for patients with bilateral SSNHL when there is concern for autoimmune disease.

Ultrasound-triggered therapeutic microbubbles enhance the efficacy of cytotoxic drugs by increasing circulation and tumor drug accumulation and limiting bioavailability and toxicity in normal tissues.

Most cancer patients receive chemotherapy at some stage of their treatment which makes improving the efficacy of cytotoxic drugs an ongoing and important goal. Despite large numbers of potent anti-cancer agents being developed, a major obstacle to clinical translation remains the inability to deliver therapeutic doses to a tumor without causing intolerable side effects. To address this problem, there has been intense interest in nanoformulations and targeted delivery to improve cancer outcomes. The aim of this work was to demonstrate how vascular endothelial growth factor receptor 2 (VEGFR2)-targeted, ultrasound-triggered delivery with therapeutic microbubbles (thMBs) could improve the therapeutic range of cytotoxic drugs. Methods: Using a microfluidic microbubble production platform, we generated thMBs comprising VEGFR2-targeted microbubbles with attached liposomal payloads for localised ultrasound-triggered delivery of irinotecan and SN38 in mouse models of colorectal cancer. Intravenous injection into tumor-bearing mice was used to examine targeting efficiency and tumor pharmacodynamics. High-frequency ultrasound and bioluminescent imaging were used to visualise microbubbles in real-time. Tandem mass spectrometry (LC-MS/MS) was used to quantitate intratumoral drug delivery and tissue biodistribution. Finally, 89Zr PET radiotracing was used to compare biodistribution and tumor accumulation of ultrasound-triggered SN38 thMBs with VEGFR2-targeted SN38 liposomes alone. Results: ThMBs specifically bound VEGFR2 in vitro and significantly improved tumor responses to low dose irinotecan and SN38 in human colorectal cancer xenografts. An ultrasound trigger was essential to achieve the selective effects of thMBs as without it, thMBs failed to extend intratumoral drug delivery or demonstrate enhanced tumor responses. Sensitive LC-MS/MS quantification of drugs and their metabolites demonstrated that thMBs extended drug exposure in tumors but limited exposure in healthy tissues, not exposed to ultrasound, by persistent encapsulation of drug prior to elimination. 89Zr PET radiotracing showed that the percentage injected dose in tumors achieved with thMBs was twice that of VEGFR2-targeted SN38 liposomes alone. Conclusions: thMBs provide a generic platform for the targeted, ultrasound-triggered delivery of cytotoxic drugs by enhancing tumor responses to low dose drug delivery via combined effects on circulation, tumor drug accumulation and exposure and altered metabolism in normal tissues.

A bioinspired peptide matrix for the detection of 2,4,6-trinitrotoluene (TNT).

A novel peptide-based three-dimensional probe called "peptide matrix," inspired by the antibody paratope region, was fabricated on a surface plasmon resonance (SPR) sensor chip to enhance the sensitivity of detecting the explosive 2,4,6-trinitrotoluene (TNT). Although peptide aptamer is an attractive candidate for a molecular recognition probe because of its ease of synthesis and chemical stability, it still has difficulty in applying to highly sensitive (i.e. parts-per-billion (ppb) or sub-ppb level) detections. Thus, we developed the concept of peptide matrix structure, which is constructed by consecutive disulfide bond formation between a large number of peptide fragments. This robust three-dimensional structure displays multiple binding sites which can efficiently associate with each TNT molecule. The peptide matrix lowered the dissociation constant (KD) by two orders of magnitude compared to the linear peptide aptamer, estimating KD as 10.1 nM, which is the lowest concentration reported by using peptide-based TNT probe. Furthermore, the concentration limit of detection of peptide matrix modified SPR sensor was 0.62 ppb, and hence comparable to single-chain variable fragment (scFv)-based TNT sensors. To our knowledge, this is the first report demonstrating peptide matrix fabrication and its application for small explosive molecule detection. This peptide matrix-based approach, which has the advantage of simple synthesis and high sensitivity, will be applicable to many other small-molecule label-free detections.

Freeze-Dried Therapeutic Microbubbles: Stability and Gas Exchange.

Microbubbles (MBs) are widely used as contrast enhancement agents for ultrasound imaging and have the potential to enhance therapeutic delivery to diseases such as cancer. Yet, they are only stable in solution for a few hours to days after production, which limits their potential application. Freeze-drying provides long-term storage, ease of transport, and consistency in structure and composition, thereby facilitating their use in clinical settings. Therapeutic microbubbles (thMBs) consisting of MBs with attached therapeutic payload potentially face even greater issues for production, stability, and well-defined drug delivery. The ability to freeze-dry thMBs represents an important step for their translation to the clinic. Here, we show that it is possible to freeze-dry and reconstitute thMBs that consist of lipid-coated MBs with an attached liposomal payload. The thMBs were produced microfluidically, and the liposomes contained either calcein, as a model drug, or gemcitabine. The results show that drug-loaded thMBs can be freeze-dried and stored for at least 6 months. Upon reconstitution, they maintain their structural integrity and drug loading. Furthermore, we show that their in vivo echogenicity is maintained post-freeze-drying. Depending on the gas used in the original bubbles, we also demonstrate that the approach provides a method to exchange the gas core to allow the formulation of thMBs with different gases for combination therapies or improved drug efficacy. Importantly, this work provides an important route for the facile off-site production of thMBs that can be reformulated at the point of care.

Molecular Effects of Glycerol on Lipid Monolayers at the Gas-Liquid Interface: Impact on Microbubble Physical and Mechanical Properties.

The production and stability of microbubbles (MBs) is enhanced by increasing the viscosity of both the formation and storage solution, respectively. Glycerol is a good candidate for biomedical applications of MBs, since it is biocompatible, although the exact molecular mechanisms of its action is not fully understood. Here, we investigate the influence glycerol has on lipid-shelled MB properties, using a range of techniques. Population lifetime and single bubble stability were studied using optical microscopy. Bubble stiffness measured by AFM compression is compared with lipid monolayer behavior in a Langmuir-Blodgett trough. We deduce that increasing glycerol concentrations enhances stability of MB populations through a 3-fold mechanism. First, binding of glycerol to lipid headgroups in the interfacial monolayer up to 10% glycerol increases MB stiffness but has limited impact on shell resistance to gas permeation and corresponding MB lifetime. Second, increased solution viscosity above 10% glycerol slows down the kinetics of gas transfer, markedly increasing MB stability. Third, above 10%, glycerol induces water structuring around the lipid monolayer, forming a glassy layer which also increases MB stiffness and resistance to gas loss. At 30% glycerol, the glassy layer is ablated, lowering the MB stiffness, but MB stability is further augmented. Although the molecular interactions of glycerol with the lipid monolayer modulate the MB lipid shell properties, MB lifetime continually increases from 0 to 30% glycerol, indicating that its viscosity is the dominant effect on MB solution stability. This three-fold action and biocompatibility makes glycerol ideal for therapeutic MB formation and storage and gives new insight into the action of glycerol on lipid monolayers at the gas-liquid interface.

Controlling the fluorescence and room-temperature phosphorescence behaviour of carbon nanodots with inorganic crystalline nanocomposites.

There is a significant drive to identify alternative materials that exhibit room temperature phosphorescence for technologies including bio-imaging, photodynamic therapy and organic light-emitting diodes. Ideally, these materials should be non-toxic and cheap, and it will be possible to control their photoluminescent properties. This was achieved here by embedding carbon nanodots within crystalline particles of alkaline earth carbonates, sulphates and oxalates. The resultant nanocomposites are luminescent and exhibit a bright, sub-second lifetime afterglow. Importantly, the excited state lifetimes, and steady-state and afterglow colours can all be systematically controlled by varying the cations and anions in the host inorganic phase, due to the influence of the cation size and material density on emissive and non-emissive electronic transitions. This simple strategy provides a flexible route for generating materials with specific, phosphorescent properties and is an exciting alternative to approaches relying on the synthesis of custom-made luminescent organic molecules.

Gross Pathology of Routine Pediatric Tonsillectomy Specimens: Optimizing the Value of Patient Care.

OBJECTIVE: This investigation seeks to evaluate the effect of gross pathologic analysis on our management of patients undergoing routine tonsillectomy and to evaluate charges and reimbursement. STUDY DESIGN: Retrospective chart review from 2005 through 2016. SETTING: Academic medical center. SUBJECTS AND METHODS: Participants were pediatric patients aged 14 years and younger undergoing tonsillectomy for either sleep-disordered breathing or tonsillitis, with tonsillectomy specimens evaluated by pathology, and without any risk factors for pediatric malignancy. Records were reviewed for demographics, surgical indications, and pathology. Abnormal reports prompted an in-depth review of the chart. Charges and reimbursement related to both hospital and professional fees for gross tonsil analysis were evaluated. RESULTS: From 2005 to 2016, 3183 routine pediatric tonsillectomy cases were performed with corresponding specimens that were sent for gross analysis revealing no significant pathologic findings; 1841 were males and 1342 were females. Ten cases underwent microscopy by pathologist order, revealing normal tonsillar tissue. The mean charge per patient for gross analysis was $60.67 if tonsils were together as 1 specimen and $77.67 if tonsils were sent as 2 separate specimens; respective reimbursement amounts were $28.74 and $35.90. CONCLUSIONS: Gross pathologic analysis did not change our management of routine pediatric tonsillectomy patients. Foregoing the practice at our institution would eliminate $19,171.72 to $24,543.72 in charges and $9081.40 to $11,344.40 in reimbursement per year. Eliminating this test would improve the value of patient care by saving health care resources without compromising clinical outcomes.

A highly reactive precursor in the iron sulfide system.

Iron sulfur (Fe-S) phases have been implicated in the emergence of life on early Earth due to their catalytic role in the synthesis of prebiotic molecules. Similarly, Fe-S phases are currently of high interest in the development of green catalysts and energy storage. Here we report the synthesis and structure of a nanoparticulate phase (FeSnano) that is a necessary solid-phase precursor to the conventionally assumed initial precipitate in the iron sulfide system, mackinawite. The structure of FeSnano contains tetrahedral iron, which is compensated by monosulfide and polysulfide sulfur species. These together dramatically affect the stability and enhance the reactivity of FeSnano.

Enhanced Tubulation of Liposome Containing Cardiolipin by MamY Protein from Magnetotactic Bacteria.

Lipid tubules are of particular interest for many potential applications in nanotechnology. Among various lipid tubule fabrication techniques, the morphological regulation of membrane structure by proteins mimicking biological processes may provide the chances to form lipid tubes with highly tuned structures. Magnetotactic bacteria synthesize magnetosomes (a unique prokaryotic organelle comprising a magnetite crystal within a lipid envelope). MamY protein is previously identified as the magnetosome protein responsible for magnetosome vesicle formation and stabilization. Furthermore, MamY is shown in vitro liposome tubulation activity. In this study, the interaction of MamY and phospholipids is investigated by using a lipids-immobilized membrane strip and a peptide array. Here, the binding of MamY to the anionic phospholipid, cardiolipin, is found and enhanced liposome tubulation efficiency. The authors propose the interaction is responsible for recruiting and locating cardiolipin to elongate liposome in vitro. The authors also suggest a similar mechanism for the invagination site in magnetosomes vesicle formation, where the lipid itself contributes further to increasing the curvature. These findings are highly important to develop an effective biomimetic synthesis technique of lipid tubules and to elucidate the unique prokaryotic organelle formation in magnetotactic bacteria.

The influence of intercalating perfluorohexane into lipid shells on nano and microbubble stability.

Microbubbles are potential diagnostic and therapeutic agents. In vivo stability is important as the bubbles are required to survive multiple passages through the heart and lungs to allow targeting and delivery. Here we have systematically varied key parameters affecting microbubble lifetime to significantly increase in vivo stability. Whilst shell and core composition are found to have an important role in improving microbubble stability, we show that inclusion of small quantities of C6F14 in the microbubble bolus significantly improves microbubble lifetime. Our results indicate that C6F14 inserts into the lipid shell, decreasing surface tension to 19 mN m(-1), and increasing shell resistance, in addition to saturating the surrounding medium. Surface area isotherms suggest that C6F14 incorporates into the acyl chain region of the lipid at a high molar ratio, indicating ∼2 perfluorocarbon molecules per 5 lipid molecules. The resulting microbubble boluses exhibit a higher in vivo image intensity compared to commercial compositions, as well as longer lifetimes.

Phospholipid dependent mechanism of smp24, an α-helical antimicrobial peptide from scorpion venom.

Determining the mechanism of action of antimicrobial peptides (AMPs) is critical if they are to be developed into the clinical setting. In recent years high resolution techniques such as atomic force microscopy (AFM) have increasingly been utilised to determine AMP mechanism of action on planar lipid bilayers and live bacteria. Here we present the biophysical characterisation of a prototypical AMP from the venom of the North African scorpion Scorpio maurus palmatus termed Smp24. Smp24 is an amphipathic helical peptide containing 24 residues with a charge of +3 and exhibits both antimicrobial and cytotoxic activity and we aim to elucidate the mechanism of action of this peptide on both membrane systems. Using AFM, quartz crystal microbalance-dissipation (QCM-D) and liposomal leakage assays the effect of Smp24 on prototypical synthetic prokaryotic (DOPG:DOPC) and eukaryotic (DOPE:DOPC) membranes has been determined. Our data points to a toroidal pore mechanism against the prokaryotic like membrane whilst the formation of hexagonal phase non-lamellar phase structures is seen in eukaryotic like membrane. Also, phase segregation is observed against the eukaryotic membrane and this study provides direct evidence of the same peptide having multiple mechanisms of action depending on the membrane lipid composition.