Subwavelength Terahertz Resonance Imaging (STRING) for Molecular Fingerprinting

Subwavelength terahertz (THz) imaging methods are highly desirable for biochemical sensing as well as materials sciences, yet sensitive spectral fingerprinting is still challenging in the frequency domain due to weak light-matter interactions. Here, we demonstrate subwavelength THz resonance imaging (STRING) that overcomes this limitation to achieve ultrasensitive molecular fingerprinting. STRING combines individual ring-shaped coaxial single resonators with near-field spectroscopy, yielding considerable sensitivity gains from both local field enhancement and the near-field effect. As an initial demonstration, we obtained spectral fingerprints from isomers of α-lactose and maltose monohydrates, achieving sensitivity that was enhanced by up to 10 orders of magnitude compared to far-field THz measurements with pelletized samples. Our results show that the STRING platform could enable the development of THz spectroscopy as a practical and sensitive tool for the fingerprinting and spectral imaging of molecules and nanoparticles.

A room-temperature polarization-sensitive CMOS terahertz camera based on quantum-dot-enhanced terahertz-to-visible photon upconversion

Detection of terahertz (THz) radiation has many potential applications, but presently available detectors are limited in many aspects of their performance, including sensitivity, speed, bandwidth and operating temperature. Most do not allow the characterization of THz polarization states. Recent observation of THz-driven luminescence in quantum dots offers a possible detection mechanism via field-driven interdot charge transfer. We demonstrate a room-temperature complementary metal-oxide-semiconductor THz camera and polarimeter based on quantum-dot-enhanced THz-to-visible upconversion mechanism with optimized luminophore geometries and fabrication designs. Besides broadband and fast responses, the nanoslit-based sensor can detect THz pulses with peak fields as low as 10 kV cm^-1. A related coaxial nanoaperture-type device shows a to-date-unexplored capability to simultaneously record the THz polarization state and field strength with similar sensitivity.

AB0344 EFFICACY OF SUBCUTANEOUS INFLIXIMAB (CT-P13 SC) COMPARED WITH INTRAVENOUS INFLIXIMAB IN RHEUMATOID ARTHRITIS: A POST-HOC ANALYSIS OF A PHASE 3 RANDOMIZED CONTROLLED TRIAL

Background

Subcutaneous (SC) CT-P13 is the first and only subcutaneous formulation of infliximab (IFX) approved by the EMA.1 In the pivotal study (NCT03147248), non-inferiority of SC IFX to intravenous (IV) was demonstrated in rheumatoid arthritis (RA) patients using 28-joint Disease Activity Score (DAS28) C-reactive protein (CRP) improvement at Week 22, with a statistically significant treatment difference of 0.27 (95% CI 0.02, 0.52) favoring the SC versus the IV arm.2,3 At Week 30, numerical differences in efficacy outcomes were shown between SC and IV IFX favoring SC IFX. IV group patients switched to SC IFX by Week 30, and the difference between the groups was reduced at Week 54.2

Objectives

To investigate whether there was a statistically significant difference between SC and IV IFX at Weeks 30 and 54 in the phase 3 pivotal study of CT-P13 SC using conservative missing imputation methods.

Methods

Patients with active RA who had an inadequate response to MTX received IV IFX 3mg/kg at Weeks 0 and 2 for induction and were randomized at a 1:1 ratio to receive SC IFX 120mg every 2 weeks or IV 3mg/kg every 8 weeks thereafter for maintenance. Patients who were randomized to receive IV IFX switched to SC at Week 30. In this post-hoc analysis, non-responder imputation (NRI) and last observation carried forward (LOCF) methods were used to investigate whether the difference in efficacy outcomes between SC and IV IFX at Weeks 30 and 54 was statistically significant. Assessments included EULAR (CRP/ESR)/ACR response; remission rate and low disease activity (LDA) rate based on DAS28 (CRP/ESR), Clinical Disease Activity Index (CDAI) and Simplified Disease Activity Index (SDAI); Boolean remission rate; and the proportion of patients achieving a minimal clinically important difference (MCID) in Health Assessment Questionnaire (HAQ).

Results

Of the 343 randomized patients, 165 patients who received SC IFX and 174 patients who received IV IFX from the efficacy population were included in the analysis. There was a statistically significant difference in SC IFX compared to IV treated patients at Week 30 using both NRI and LOCF methods in almost all the clinical variables. However, the difference in efficacy outcomes between SC IFX and IV was reduced at Week 54 after the IV group switched to SC. This supports the improved efficacy of SC IFX at Week 30. Some of the key results (EULAR [CRP] responses, LDA rates based on DAS28 [CRP], CDAI, and SDAI) were presented in Figure 1. Analysis using LOCF and NRI methods yielded consistent results across most of the efficacy outcomes.

Figure 1.

Comparison of clinical outcomes between SC IFX and IV IFX in patients with active rheumatoid arthritis.

*P<0.05.

P-value for difference in proportion between SC and IV treatment group was obtained by asymptotic Wald test.

Low disease activity based on DAS28 (CRP) (< 3.2), CDAI (eatment group AI (≤ 11.0).

Conclusion

Statistical analyses using conservative missing imputation methods showed significantly greater improvements in clinical outcomes with SC IFX compared to IV at Week 30 in patients with RA. Between-group differences was reduced at Week 54, suggesting improved responses after switching from IV to SC.

References

[1]Remsima summary of product characteristics. https://www.ema.europa.eu/en/documents/product-information/remsima-epar-product-information_en.pdf. Published 2021. Accessed 10 January 2022.

[2]Westhovens R, Wiland P, Zawadzki M, et al. Efficacy, pharmacokinetics and safety of subcutaneous versus intravenous CT-P13 in rheumatoid arthritis: a randomized phase I/III trial. Rheumatology (Oxford). 2021;60(5):2277-2287.

[3]Combe B, Allanore Y, Alten R, et al. Comparative efficacy of subcutaneous (CT-P13) and intravenous infliximab in adult patients with rheumatoid arthritis: a network meta-regression of individual patient data from two randomised trials. Arthritis Res Ther. 2021;23(1):119.

Disclosure of Interests

Arnaud Constantin Speakers bureau: Abbvie, Amgen, Boehringer, Celltrion, Galapagos, Janssen, Lilly, Novartis, Sanofi, UCB, Consultant of: Abbvie, Amgen, Boehringer, Celltrion, Galapagos, Janssen, Lilly, Novartis, Sanofi, UCB, Roberto Caporali Speakers bureau: Abbvie, Amgen, BMS, Celltrion, Galapagos, Lilly, Pfizer, Fresenius-Kabi, MSD, UCB, Roche,Janssen, Novartis, Sandoz, Consultant of: Abbvie, Amgen, BMS, Celltrion, Galapagos, Lilly, Pfizer, MSD, UCB, Janssen, Novartis, Sandoz, Christopher John Edwards Speakers bureau: Abbvie, Astra Zeneca, Celltrion, Chugai, Fresenius, Galapagos, Gilead, GSK, Lilly, Janssen, Pfizer, Roche, Consultant of: Abbvie, Astra Zeneca, Chugai, Galapagos, Gilead, GSK, Lilly, Janssen, Pfizer, Roche, Grant/research support from: Celltrion, Pfizer, Abbvie, Joao Eurico Fonseca Speakers bureau: Abbvie, Ache, Janssen, Lilly, Medac, Novartis, Pfizer, Consultant of: Abbvie, Celltrion, Janssen, Lilly, Pfizer, Grant/research support from: Abbvie, Janssen, Lilly, MSD, Novartis, Pfizer, Roche, Florenzo Iannone Speakers bureau: Abbvie, BMS, Celltrion, Galapagos, MSD, Eli-Lilly, Janssen, Novartis, Pfizer, UCB, Consultant of: Abbvie, BMS, Celltrion, Galapagos, MSD, Eli-Lilly, Janssen, Pfizer, Grant/research support from: BMS, MSD, Edward Keystone Speakers bureau: Amgen, AbbVie, Celltrion, F. Hoffmann-La Roche Inc., Janssen Inc., Merck, Pfizer Pharmaceuticals, Sandoz, Sanofi Genzyme, Consultant of: AbbVie, Amgen, Celltrion, Myriad Autoimmune, F. Hoffmann-La Roche Inc, Janssen Inc, Lilly Pharmaceuticals, Merck, Pfizer Pharmaceuticals, Sandoz, Sanofi-Genzyme, Samsung Bioepsis, Grant/research support from: Amgen, Merck, Pfizer Pharmaceuticals, Hendrik Schulze-Koops Consultant of: Celltrion, Taeksang Kwon Employee of: Celltrion Healthcare, Seungmin Kim Employee of: Celltrion Healthcare, Sangwook Yoon Employee of: Celltrion Healthcare, Dong-Hyeon Kim Employee of: Celltrion Healthcare, Gahee Park Employee of: Celltrion Inc., DaeHyun Yoo Speakers bureau: Celltrion, Celltrion Healthcare

Nano-Optical Tweezers: Methods and Applications for Trapping Single Molecules and Nanoparticles

The front cover artwork is provided by Prof. Sang-Hyun Oh's group at the University of Minnesota. The image shows the optical trapping of chiral nanoparticles using coaxial nano-optical tweezers, devices capable of harnessing light to manipulate objects a few nanometers in size. Read the full text of the Review at 10.1002/cphc.202100004.

Nano-Optical Tweezers: Methods and Applications for Trapping Single Molecules and Nanoparticles

Optical tweezers were developed in 1970 by Arthur Ashkin as a tool for the manipulation of micron-sized particles. Ashkin's original design was then adapted for a variety of purposes, such as trapping and manipulation of biological materials^[1] and the laser cooling of atoms.^[2,3] More recent development has led to nano-optical tweezers, for trapping particles on the scale of only a few nanometers, and holographic tweezers, which allow for dynamic control of multiple traps in real-time. These alternatives to conventional optical tweezers have made it possible to trap single molecules and to perform a variety of studies on them. Presented here is a review of recent developments in nano-optical tweezers and their current and future applications.

POS0911 SIMILAR CLINICAL RESPONSES ACHIEVED WITH LOWER VERSUS STANDARD DOSES OF INFLIXIMAB BIOSIMILAR CT-P13 IN PATIENTS WITH ANKYLOSING SPONDYLITIS: REAL-WORLD RESULTS FROM THE RAAS STUDY

Background:

CT-P13, an infliximab biosimilar, is effective for treating ankylosing spondylitis (AS) at a dose of 5 mg/kg infused once every 6–8 weeks. Evidence suggests that patients with AS may benefit from a lower dose, and individualised dose/interval adjustments should be based on treatment response.

Objectives:

To analyse real-world treatment patterns (doses and infusion intervals) and outcomes for CT-P13-treated patients with AS over 5 years.

Methods:

The RAAS study collected medical record data for adults with AS treated with CT-P13 at five referral hospitals in the Republic of Korea (2012–2017). Patients were infliximab naïve at CT-P13 initiation (‘naïve’) or had switched to CT-P13 from reference infliximab (‘switched’). Patients were analysed by baseline dose (BD) (<4 mg/kg; ≥4–<5 mg/kg; ≥5 mg/kg), defined as the third (naïve) or first (switched) infusion dose. Baseline infusion intervals were the average of the three infusion intervals after BD. Over time, patients with both constant dose and infusion interval were compared with those with changes in dose and/or infusion interval. Data were analysed by Kruskal–Wallis test, chi-squared test and one-way analysis of variance, and drug survival by log-rank test.

Results:

Overall, 337 patients (219 naïve; 118 switched) were identified. Of those with BD data, 71, 117 and 82 patients had BDs of <4 mg/kg, ≥4–<5 mg/kg and ≥5 mg/kg, respectively. Most patients were male (74.8%). Patients with higher BDs tended to have higher Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores; switched patients had lower scores than naïve patients. Of 186 evaluable patients (118 naïve; 68 switched), 85 (46 naïve; 39 switched) did not have dose and/or interval changes (‘combined constant’ group). More naïve (n=72; 61.0%) versus switched (n=29; 42.6%) patients had dose and/or interval changes (‘combined changed’ group). Considering dose and interval separately, 18/235 evaluable patients (152 naïve; 83 switched) had dose changes (12 increased; 6 decreased) and 110/224 evaluable patients (140 naïve; 84 switched) had interval changes (79 increased; 31 decreased). Cumulative annual doses were similar between naïve and switched patients; switched patients had longer infusion intervals than naïve patients (Figure 1). There were no significant differences in drug survival between BD groups overall or for naïve and switched patients. BASDAI scores over time showed that disease activity was well controlled (Table 1). Patients in the combined changed versus combined constant group had greater improvements in BASDAI score.

Table 1.

BASDAI scores

GroupStatisticW0W54W102W156W210Combined constantTotal (N=85)n7273574231Mean (SD)5.50 (3.12)2.50 (1.71)2.35 (1.66)2.42 (1.66)2.36 (1.68)Median6.322.602.402.552.60Naïve (n=46)n3939261812Mean (SD)7.86 (1.45)2.49 (1.82)2.41 (1.75)2.34 (1.70)1.94 (1.58)Median7.802.201.751.901.44Switched (n=39)n3334312419Mean (SD)2.71 (2.07)2.50 (1.60)2.31 (1.60)2.48 (1.67)2.63 (1.73)Median2.582.752.502.802.70Combined changedTotal (N=101)n8785765335Mean (SD)5.68 (2.89)1.81 (1.45)1.58 (1.27)1.49 (1.34)1.40 (1.24)Median6.701.321.191.201.00Naïve (n=72)n6360543418Mean (SD)7.18 (1.37)2.01 (1.44)1.65 (1.22)1.54 (1.26)1.52 (0.97)Median7.301.831.351.311.35Switched (n=29)n2425221917Mean (SD)1.74 (1.94)1.33 (1.36)1.42 (1.41)1.39 (1.50)1.28 (1.50)Median0.920.800.850.700.58

SD, standard deviation; W, Week

Conclusion:

These real-world data demonstrate that adjusting dose and infusion interval can improve clinical outcomes for CT-P13-treated patients with AS. Drug survival and BASDAI results show that patients with lower baseline BASDAI receiving low CT-P13 doses can achieve the same outcomes as those dosed with ≥5 mg/kg. Findings support the lack of impact of switching from reference infliximab to CT-P13 on efficacy, underlining conclusions previously drawn for efficacy and safety.1

References:

[1]Kim T-H, et al. Clin Drug Investig 2020;40:541–53.

Acknowledgements:

Funding: This study was supported by Celltrion Healthcare Co., Ltd. (Incheon, Republic of Korea). Medical writing support was provided by Beatrice Tyrrell, DPhil (Aspire Scientific, Bollington, UK), and funded by Celltrion Healthcare Co., Ltd. (Incheon, Republic of Korea).

Disclosure of Interests:

Shin-Seok Lee: None declared, Tae-Hwan Kim: None declared, Won Park Consultant of: Celltrion, Inc., Yeong Wook Song: None declared, Chang-Hee Suh Speakers bureau: AbbVie Inc., Astellas Pharma Inc., Samsung Bioepis Co., Ltd, Consultant of: Celltrion Healthcare Co., Ltd., Eli Lilly and Company, GlaxoSmithKline plc, Janssen Pharmaceuticals, Yungjin Pharmaceutical, Co., Ltd, SooKyoung Kim Shareholder of: Celltrion Healthcare Co., Ltd., Employee of: Celltrion Healthcare Co., Ltd., DaeHyun Yoo Speakers bureau: Celltrion, Consultant of: Celltrion, Grant/research support from: Celltrion

Plasmonic Split-Trench Resonator for Trapping and Sensing

On-chip integration of plasmonics and electronics can benefit a broad range of applications in biosensing, signal processing, and optoelectronics. A key requirement is a chip-scale manufacturing method. Here, we demonstrate a split-trench resonator platform that combines a high-quality-factor resonant plasmonic biosensor with radio frequency (RF) nanogap tweezers. The split-trench resonator can simultaneously serve as a dielectrophoretic trap and a nanoplasmonic sensor. Trapping is accomplished by applying an RF electrical bias across a 10 nm gap, thereby either attracting or repelling analytes. Trapped analytes are detected in a label-free manner using refractive-index sensing, enabled by interference between surface-plasmon standing waves in the trench and light transmitted through the gap. This active sample concentration mechanism enables detection of nanoparticles and proteins at a concentration as low as 10 pM. We can manufacture centimeter-long split-trench cavity resonators with high throughput via photolithography and atomic layer deposition, toward practical applications in biosensing, spectroscopy, and optoelectronics.

Escalated Photocurrent with Excitation Energy in Dual-Gated MoTe2

Although van der Waals-layered transition metal dichalcogenides from transient absorption spectroscopy have successfully demonstrated an ideal carrier multiplication (CM) performance with an onset of nearly 2E_g, interpretation of the CM effect from the optical approach remains unresolved owing to the complexity of many-body electron-hole pairs. We demonstrate the escalated photocurrent with excitation photon energy by fabricating the dual-gate p-n junction of a MoTe₂ film on a transparent substrate. Electrons and holes were efficiently extracted by eliminating the Schottky barriers in the metal contact and minimizing multiple reflections. The photocurrent was elevated proportionately to the excitation photon energy. The boosted quantum efficiency confirms the multiple electron-hole pair generation of >2E_g, consistent with CM results from an optical approach, pushing the solar cell efficiency beyond the Shockley-Queisser limit.

Real-space imaging of acoustic plasmons in large-area graphene grown by chemical vapor deposition

An acoustic plasmon mode in a graphene-dielectric-metal structure has recently been spotlighted as a superior platform for strong light-matter interaction. It originates from the coupling of graphene plasmon with its mirror image and exhibits the largest field confinement in the limit of a sub-nm-thick dielectric. Although recently detected in the far-field regime, optical near-fields of this mode are yet to be observed and characterized. Here, we demonstrate a direct optical probing of the plasmonic fields reflected by the edges of graphene via near-field scattering microscope, revealing a relatively small propagation loss of the mid-infrared acoustic plasmons in our devices that allows for their real-space mapping at ambient conditions even with unprotected, large-area graphene grown by chemical vapor deposition. We show an acoustic plasmon mode that is twice as confined and has 1.4 times higher figure of merit in terms of the normalized propagation length compared to the graphene surface plasmon under similar conditions. We also investigate the behavior of the acoustic graphene plasmons in a periodic array of gold nanoribbons. Our results highlight the promise of acoustic plasmons for graphene-based optoelectronics and sensing applications.

THU0186 CLINICAL EVALUATION OF THE IMMUNOGENICITY TO CT-P13 FOR SUBCUTANEOUS USE IN PATIENTS WITH ACTIVE RHEUMATOID ARTHRITIS: 1-YEAR CLINICAL RESULTS FROM A MULTICENTER, RANDOMIZED CONTROLLED PIVOTAL TRIAL

Background:

Novel subcutaneous infliximab (CT-P13 SC) was developed to augment the flexibility in therapeutic use of infliximab and noninferiority (NI) of CT-P13 SC versus CT-P13 intravenous (IV) was demonstrated for efficacy in patients with rheumatoid arthritis (RA) [1]. CT-P13 SC 120mg biweekly showed consistent higher therapeutic trough levels during the treatment period, which helps in maintaining efficacy over time. Since immunogenicity has clinical importance in patients using anti-TNF alpha agents and there is a general presumption that SC route is more immunogenic than IV route, this needs careful assessment.

Objectives:

Immunogenicity assessment of CT-P13 SC with further impact analysis has been performed on the pivotal data set [1] to determine whether there was any correlation between the magnitude of anti-drug antibody (ADA) positivity and clinical outcomes in RA patients.

Methods:

The immune response against CT-P13 in human serum was detected using an electrochemiluminescence (ECL) platform with an Affinity Capture Elution (ACE) step. An ADA ECL ACE assay showed ability to detect ADA at low levels in all samples regardless of residual drug in serum (25 ng/mL ADA in the presence of 80 μg/mL of CT-P13 in RA serum). To investigate the impact of ADA titer on PK, efficacy and safety, key clinical parameters were assessed by visit based ADA titer quartile. All patients who had ‘Positive’ ADA status result at each visit were included in the analysis and categorized into 4 groups using the 25th, 50th, 75th percentiles of ADA titer result, respectively.

Results:

The four subgroups categorized by quartiles at each visit from week 22 to week 54 were: 1st (ADA titer ≤ 3), 2nd (3 < ADA titer ≤ 9), 3rd (9 < ADA titer ≤ 27) and 4th (27 < ADA titer). There was a trend for pre-dose concentration to decrease as ADA titer increases for both CT-P13 SC and CT-P13 IV arms as expected (Figure 1). Patients in the 1st and 2nd subgroup maintained the sufficient therapeutic drug concentration level. Figure 2 shows the correlation between ADA titer and efficacy outcomes where the change from baseline of DAS28 (CRP) and the proportion of patients achieving ACR20 were lower in the 3rd and 4th subgroups. The ADA impact was especially apparent in the 4th subgroup where the mean pre-dose concentration of the patients was below the therapeutic drug concentration level (1 μg/mL), which led to worse efficacy outcomes in both arms, IV as well as SC. Nevertheless, no impact of ADA on safety profile in both arms was observed. A neutralizing antibody (NAb) method with enhanced drug tolerance but limited performance was also developed and clinical consequences of NAb titer in terms of PK, efficacy and safety were not different from the results with ADA.

Conclusion:

The analysis of both ADA positivity and titer is clinically meaningful in the prediction of PK profile and clinical response. CT-P13 SC administration did not result in a greater incidence of ADA compared to the CT-P13 IV and there were no clinical differences depending on the formulation.

References:

[1]Westhovens R, et al. Annals of the Rheumatic Diseases 2019;78:1158-1159.

Disclosure of Interests:

Rene Westhovens Grant/research support from: Celltrion Inc, Galapagos, Gilead, Consultant of: Celltrion Inc, Galapagos, Gilead, Speakers bureau: Celltrion Inc, Galapagos, Gilead, DaeHyun Yoo Grant/research support from: Celltrion, Inc, Consultant of: Celltrion, Inc, Speakers bureau: Celltrion Healthcare, Inc, Piotr Wiland Grant/research support from: Celltrion, Inc, Speakers bureau: Novartis, Pfizer, Abbvie, Gedeon-Richter, Lilly, Roche, Sandoz, Marek Zawadzki Grant/research support from: Celltrion, Inc, Delina Ivanova Grant/research support from: Celltrion, Inc, Alfredo Berrocal Grant/research support from: Celltrion, Inc, Speakers bureau: Pfizer, Elias Chalouhi Grant/research support from: Celltrion, Inc, Éva Balázs Grant/research support from: Celltrion, Inc, Consultant of: Amgen, Sergii Shevchuk Grant/research support from: Celltrion, Inc, Sang Joon Lee Shareholder of: Celltrion, Inc, Employee of: Celltrion, Inc, Sung Hyun Kim Shareholder of: Celltrion, Inc, Employee of: Celltrion, Inc, JeeHye Suh Employee of: Celltrion, Inc, Chankyoung Hwang Employee of: Celltrion, Inc, Dae Seok Choi Shareholder of: Celltrion, Inc, Employee of: Celltrion, Inc

Terahertz and infrared nonlocality and field saturation in extreme-scale nanoslits

With advances in nanofabrication techniques, extreme-scale nanophotonic devices with critical gap dimensions of just 1-2 nm have been realized. The plasmonic response in these extreme-scale gaps is significantly affected by nonlocal electrodynamics, quenching field enhancement and blue-shifting the resonance with respect to a purely local behavior. The extreme mismatch in lengthscales, ranging from millimeter-long wavelengths to atomic-scale charge distributions, poses a daunting computational challenge. In this paper, we perform computations of a single nanoslit using the hybridizable discontinuous Galerkin method to solve Maxwell's equations augmented with the hydrodynamic model for the conduction-band electrons in noble metals. This method enables the efficient simulation of the slit while accounting for the nonlocal interactions between electrons and the incident light. We study the impact of gap width, film thickness and electron motion model on the plasmon resonances of the slit for two different frequency regimes: (1) terahertz frequencies, which lead to 1000-fold field amplitude enhancements that saturate as the gap shrinks; and (2) the near- and mid-infrared regime, where we show that narrow gaps and thick films cluster Fabry-Pérot (FP) resonances towards lower frequencies, derive a dispersion relation for the first FP resonance, in addition to observing that nonlocality boosts transmittance and reduces enhancement.

Modeling and observation of mid-infrared nonlocality in effective epsilon-near-zero ultranarrow coaxial apertures

With advances in nanofabrication techniques, extreme-scale nanophotonic devices with critical gap dimensions of just 1-2 nm have been realized. Plasmons in such ultranarrow gaps can exhibit nonlocal response, which was previously shown to limit the field enhancement and cause optical properties to deviate from the local description. Using atomic layer lithography, we create mid-infrared-resonant coaxial apertures with gap sizes as small as 1 nm and observe strong evidence of nonlocality, including spectral shifts and boosted transmittance of the cutoff epsilon-near-zero mode. Experiments are supported by full-wave 3-D nonlocal simulations performed with the hybridizable discontinuous Galerkin method. This numerical method captures atomic-scale variations of the electromagnetic fields while efficiently handling extreme-scale size mismatch. Combining atomic-layer-based fabrication techniques with fast and accurate numerical simulations provides practical routes to design and fabricate highly-efficient large-area mid-infrared sensors, antennas, and metasurfaces.

Graphene acoustic plasmon resonator for ultrasensitive infrared spectroscopy

One of the fundamental hurdles in plasmonics is the trade-off between electromagnetic field confinement and the coupling efficiency with free-space light, a consequence of the large momentum mismatch between the excitation source and plasmonic modes. Acoustic plasmons in graphene, in particular, have an extreme level of field confinement, as well as an extreme momentum mismatch. Here, we show that this fundamental compromise can be overcome and demonstrate a graphene acoustic plasmon resonator with nearly perfect absorption (94%) of incident mid-infrared light. This high efficiency is achieved by utilizing a two-stage coupling scheme: free-space light coupled to conventional graphene plasmons, which then couple to ultraconfined acoustic plasmons. To realize this scheme, we transfer unpatterned large-area graphene onto template-stripped ultraflat metal ribbons. A monolithically integrated optical spacer and a reflector further boost the enhancement. We show that graphene acoustic plasmons allow ultrasensitive measurements of absorption bands and surface phonon modes in ångström-thick protein and SiO₂ layers, respectively. Our acoustic plasmon resonator platform is scalable and can harness the ultimate level of light-matter interactions for potential applications including spectroscopy, sensing, metasurfaces and optoelectronics.

Waveguide-Integrated Compact Plasmonic Resonators for On-Chip Mid-Infrared Laser Spectroscopy

The integration of nanoplasmonic devices with a silicon photonic platform affords a new approach for efficient light delivery by combining the high field enhancement of plasmonics and the ultralow propagation loss of dielectric waveguides. Such a hybrid integration obviates the need for a bulky free-space optics setup and can lead to fully integrated, on-chip optical sensing systems. Here, we demonstrate ultracompact plasmonic resonators directly patterned atop a silicon waveguide for mid-infrared spectroscopic chemical sensing. The footprint of the plasmonic nanorod resonators is as small as 2 μm², yet they can couple with the mid-infrared waveguide mode efficiently. The plasmonic resonance is directly measured through the transmission spectrum of the waveguide with a coupling efficiency greater than 70% and a field intensity enhancement factor of over 3600 relative to the evanescent waveguide field intensity. Using this hybrid device and a tunable mid-infrared laser source, surface-enhanced infrared absorption spectroscopy of both a thin poly(methyl methacrylate) film and an octadecanethiol monolayer is successfully demonstrated.

Waveguide-integrated mid-infrared plasmonics with high-efficiency coupling for ultracompact surface-enhanced infrared absorption spectroscopy

Waveguide-integrated plasmonics is a growing field with many innovative concepts and demonstrated devices in the visible and near-infrared. Here, we extend this body of work to the mid-infrared for the application of surface-enhanced infrared absorption (SEIRA), a spectroscopic method to probe molecular vibrations in small volumes and thin films. Built atop a silicon-on-insulator (SOI) waveguide platform, two key plasmonic structures useful for SEIRA are examined using computational modeling: gold nanorods and coaxial nanoapertures. We find resonance dips of 90% in near diffraction-limited areas due to arrays of our structures and up to 50% from a single resonator. Each of the structures is evaluated using the simulated SEIRA signal from poly(methyl methacrylate) and an octadecanethiol self-assembled monolayer. The platforms we present allow for a compact, on-chip SEIRA sensing system with highly efficient waveguide coupling in the mid-IR.

Low-Power Optical Trapping of Nanoparticles and Proteins with Resonant Coaxial Nanoaperture Using 10 nm Gap

We present optical trapping with a 10 nm gap resonant coaxial nanoaperture in a gold film. Large arrays of 600 resonant plasmonic coaxial nanoaperture traps are produced on a single chip via atomic layer lithography with each aperture tuned to match a 785 nm laser source. We show that these single coaxial apertures can act as efficient nanotweezers with a sharp potential well, capable of trapping 30 nm polystyrene nanoparticles and streptavidin molecules with a laser power as low as 4.7 mW. Furthermore, the resonant coaxial nanoaperture enables real-time label-free detection of the trapping events via simple transmission measurements. Our fabrication technique is scalable and reproducible, since the critical nanogap dimension is defined by atomic layer deposition. Thus our platform shows significant potential to push the limit of optical trapping technologies.

Resolving molecule-specific information in dynamic lipid membrane processes with multi-resonant infrared metasurfaces

A multitude of biological processes are enabled by complex interactions between lipid membranes and proteins. To understand such dynamic processes, it is crucial to differentiate the constituent biomolecular species and track their individual time evolution without invasive labels. Here, we present a label-free mid-infrared biosensor capable of distinguishing multiple analytes in heterogeneous biological samples with high sensitivity. Our technology leverages a multi-resonant metasurface to simultaneously enhance the different vibrational fingerprints of multiple biomolecules. By providing up to 1000-fold near-field intensity enhancement over both amide and methylene bands, our sensor resolves the interactions of lipid membranes with different polypeptides in real time. Significantly, we demonstrate that our label-free chemically specific sensor can analyze peptide-induced neurotransmitter cargo release from synaptic vesicle mimics. Our sensor opens up exciting possibilities for gaining new insights into biological processes such as signaling or transport in basic research as well as provides a valuable toolkit for bioanalytical and pharmaceutical applications.

Neutropenia following Perioperative Intraperitoneal Chemotherapy

Introduction

The purpose of this retrospective report was to evaluate clinical features associated with profound neutropenia in patients with peritoneal carcinomatosis who were treated with heated intraoperative intraperitoneal chemotherapy (HIIC) followed by early postoperative intraperitoneal chemotherapy (EPIC). Common clinical denominators for significant neutropenia were analyzed.

Materials and Methods

A retrospective study of all available clinical data of six patients with postoperative neutropenia out of a total of 242 was undertaken. All patients underwent cytoreductive surgery, HIIC with mitomycin C (n = 4) or cisplatin (n = 1) and EPIC with 5-fluorouracil (5-FU) for 4 (n = 1) or 5 (n = 5) days.

Results

All six patients presented with hematologic toxicity of WHO criteria grade 4; four of them died postoperatively. Two of the patients who died, and one who did not die, developed bowel perforations. Five patients had prior chemotherapy with 5-FU; three of them had toxic side effects. All patients were overweight, and three patients were anemic preoperatively. The neutropenia presented with fever, leukopenia and thrombocytopenia on postoperative days 10–15. The leukocyte count courses showed a pattern suggesting the 5-FU as the cause of leukopenia. There was no consistent warning signal for predicting severe neutropenia.

Discussion

Neutropenia following cytoreductive surgery combined with HIIC and EPIC has a high mortality (66%). Patients who are at special risk and should have a dose reduction include patients who had toxicities from prior chemotherapy, who present with obesity and anemia. The groups have an increased risk of developing postoperative profound neutropenia. This condition can result in a prohibitively high mortality and morbidity rate. Therefore, reduced doses of chemotherapy in selected patients are necessary to prevent this condition from developing.

Ultrasmall Plasmonic Single Nanoparticle Light Source Driven by a Graphene Tunnel Junction

Metal nanoparticles that can couple light into tightly confined surface plasmons bridge the size mismatch between the wavelength of light and nanostructures are one of the smallest building blocks of nano-optics. However, plasmonic nanoparticles have been primarily studied to concentrate or scatter incident light as an ultrasmall antenna, while studies of their intrinsic plasmonic light emission properties have been limited. Although light emission from plasmonic structures can be achieved by inelastic electron tunneling, this strategy cannot easily be applied to isolated single nanoparticles due to the difficulty in making electrical connections without disrupting the particle plasmon mode. Here, we solve this problem by placing gold nanoparticles on a graphene tunnel junction. The monolayer graphene provides a transparent counter electrode for tunneling while preserving the ultrasmall footprint and plasmonic mode of nanoparticle. The tunneling electrons excite the plasmonic mode, followed by radiative decay of the plasmon. We also demonstrate that a dielectric overlayer atop the graphene tunnel junction can be used to tune the light emission. We show the simplicity and scalability of this approach by achieving electroluminescence from single nanoparticles without bulky contacts as well as millimeter-sized arrays of nanoparticles.

High-Contrast Infrared Absorption Spectroscopy via Mass-Produced Coaxial Zero-Mode Resonators with Sub-10 nm Gaps

We present a wafer-scale array of resonant coaxial nanoapertures as a practical platform for surface-enhanced infrared absorption spectroscopy (SEIRA). Coaxial nanoapertures with sub-10 nm gaps are fabricated via photolithography, atomic layer deposition of a sacrificial Al₂O₃ layer to define the nanogaps, and planarization via glancing-angle ion milling. At the zeroth-order Fabry-Pérot resonance condition, our coaxial apertures act as a "zero-mode resonator (ZMR)", efficiently funneling as much as 34% of incident infrared (IR) light along 10 nm annular gaps. After removing Al₂O₃ in the gaps and inserting silk protein, we can couple the intense optical fields of the annular nanogap into the vibrational modes of protein molecules. From 7 nm gap ZMR devices coated with a 5 nm thick silk protein film, we observe high-contrast IR absorbance signals drastically suppressing 58% of the transmitted light and infer a strong IR absorption enhancement factor of 10⁴∼10⁵. These single nanometer gap ZMR devices can be mass-produced via batch processing and offer promising routes for broad applications of SEIRA.

Three-Dimensional Integration of Black Phosphorus Photodetector with Silicon Photonics and Nanoplasmonics

We demonstrate the integration of a black phosphorus photodetector in a hybrid, three-dimensional architecture of silicon photonics and metallic nanoplasmonics structures. This integration approach combines the advantages of the low propagation loss of silicon waveguides, high-field confinement of a plasmonic nanogap, and the narrow bandgap of black phosphorus to achieve high responsivity for detection of telecom-band, near-infrared light. Benefiting from an ultrashort channel (∼60 nm) and near-field enhancement enabled by the nanogap structure, the photodetector shows an intrinsic responsivity as high as 10 A/W afforded by internal gain mechanisms, and a 3 dB roll-off frequency of 150 MHz. This device demonstrates a promising approach for on-chip integration of three distinctive photonic systems, which, as a generic platform, may lead to future nanophotonic applications for biosensing, nonlinear optics, and optical signal processing.

High-Throughput Fabrication of Resonant Metamaterials with Ultrasmall Coaxial Apertures via Atomic Layer Lithography

We combine atomic layer lithography and glancing-angle ion polishing to create wafer-scale metamaterials composed of dense arrays of ultrasmall coaxial nanocavities in gold films. This new fabrication scheme makes it possible to shrink the diameter and increase the packing density of 2 nm-gap coaxial resonators, an extreme subwavelength structure first manufactured via atomic layer lithography, both by a factor of 100 with respect to previous studies. We demonstrate that the nonpropagating zeroth-order Fabry-Pérot mode, which possesses slow light-like properties at the cutoff resonance, traps infrared light inside 2 nm gaps (gap volume ∼ λ(3)/10(6)). Notably, the annular gaps cover only 3% or less of the metal surface, while open-area normalized transmission is as high as 1700% at the epsilon-near-zero (ENZ) condition. The resulting energy accumulation alongside extraordinary optical transmission can benefit applications in nonlinear optics, optical trapping, and surface-enhanced spectroscopies. Furthermore, because the resonance wavelength is independent of the cavity length and dramatically red shifts as the gap size is reduced, large-area arrays can be constructed with λresonance ≫ period, making this fabrication method ideal for manufacturing resonant metamaterials.

Plasmonic Nanohole Sensor for Capturing Single Virus-Like Particles toward Virucidal Drug Evaluation

A plasmonic nanohole sensor for virus-like particle capture and virucidal drug evaluation is reported. Using a materials-selective surface functionalization scheme, passive immobilization of virus-like particles only within the nanoholes is achieved. The findings demonstrate that a low surface coverage of particles only inside the functionalized nanoholes significantly improves nanoplasmonic sensing performance over conventional nanohole arrays.

Infrared Plasmonic Biosensor for Real-Time and Label-Free Monitoring of Lipid Membranes

In this work, we present an infrared plasmonic biosensor for chemical-specific detection and monitoring of biomimetic lipid membranes in a label-free and real-time fashion. Lipid membranes constitute the primary biological interface mediating cell signaling and interaction with drugs and pathogens. By exploiting the plasmonic field enhancement in the vicinity of engineered and surface-modified nanoantennas, the proposed biosensor is able to capture the vibrational fingerprints of lipid molecules and monitor in real time the formation kinetics of planar biomimetic membranes in aqueous environments. Furthermore, we show that this plasmonic biosensor features high-field enhancement extending over tens of nanometers away from the surface, matching the size of typical bioassays while preserving high sensitivity.

Template-Stripped Tunable Plasmonic Devices on Stretchable and Rollable Substrates

We use template stripping to integrate metallic nanostructures onto flexible, stretchable, and rollable substrates. Using this approach, high-quality patterned metals that are replicated from reusable silicon templates can be directly transferred to polydimethylsiloxane (PDMS) substrates. First we produce stretchable gold nanohole arrays and show that their optical transmission spectra can be modulated by mechanical stretching. Next we fabricate stretchable arrays of gold pyramids and demonstrate a modulation of the wavelength of light resonantly scattered from the tip of the pyramid by stretching the underlying PDMS film. The use of a flexible transfer layer also enables template stripping using a cylindrical roller as a substrate. As an example, we demonstrate roller template stripping of metallic nanoholes, nanodisks, wires, and pyramids onto the cylindrical surface of a glass rod lens. These nonplanar metallic structures produced via template stripping with flexible and stretchable films can facilitate many applications in sensing, display, plasmonics, metasurfaces, and roll-to-roll fabrication.

Lipid Membrane Deformation Accompanied by Disk-to-Ring Shape Transition of Cholesterol-Rich Domains

During vesicle budding or endocytosis, biomembranes undergo a series of lipid- and protein-mediated deformations involving cholesterol-enriched lipid rafts. If lipid rafts of high bending rigidities become confined to the incipient curved membrane topology such as a bud-neck interface, they can be expected to reform as ring-shaped rafts. Here, we report on the observation of a disk-to-ring shape morpho-chemical transition of a model membrane in the absence of geometric constraints. The raft shape transition is triggered by lateral compositional heterogeneity and is accompanied by membrane deformation in the vertical direction, which is detected by height-sensitive fluorescence interference contrast microscopy. Our results suggest that a flat membrane can become curved simply by dynamic changes in local chemical composition and shape transformation of cholesterol-rich domains.

A natural human IgM that binds to gangliosides is therapeutic in murine models of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating, fatal neurological disease that primarily affects spinal cord anterior horn cells and their axons for which there is no treatment. Here we report the use of a recombinant natural human IgM that binds to the surface of neurons and supports neurite extension, rHIgM12, as a therapeutic strategy in murine models of human ALS. A single 200 µg intraperitoneal dose of rHIgM12 increases survival in two independent genetic-based mutant SOD1 mouse strains (SOD1G86R and SOD1G93A) by 8 and 10 days, delays the onset of neurological deficits by 16 days, delays the onset of weight loss by 5 days, and preserves spinal cord axons and anterior horn neurons. Immuno-overlay of thin layer chromatography and surface plasmon resonance show that rHIgM12 binds with high affinity to the complex gangliosides GD1a and GT1b. Addition of rHIgM12 to neurons in culture increases α-tubulin tyrosination levels, suggesting an alteration of microtubule dynamics. We previously reported that a single peripheral dose of rHIgM12 preserved neurological function in a murine model of demyelination with axon loss. Because rHIgM12 improves three different models of neurological disease, we propose that the IgM might act late in the cascade of neuronal stress and/or death by a broad mechanism.

Summary: A single peripheral dose of a recombinant natural human IgM increases lifespan and delays neurological deficits in mouse models of human ALS.

Effect of low speed drilling on osseointegration using simplified drilling procedures

Our aim was to find out whether simplified drilling protocols would provide biological responses comparable to those of conventional drilling protocols at the low rotational speed of 400rpm. Seventy-eight root form endosseous implants with diameters of 3.75, 4.2, and 5mm were placed into canine tibias and allowed to heal for 3 and 5 weeks. After the dogs had been killed, the samples of implanted bone were retrieved and processed for non-decalcified histological sectioning. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) analyses were made on the histological sections. Implants treated by the simplified protocol resulted in BIC and BAFO values comparable to those obtained with the conventional drilling protocol, and there were no significant differences in the technique or diameter of the drilling. The results suggest that the simplified procedure gives biological outcomes comparable to those of the conventional procedure.

Dielectrophoresis-enhanced plasmonic sensing with gold nanohole arrays

We experimentally demonstrate dielectrophoretic concentration of biological analytes on the surface of a gold nanohole array, which concurrently acts as a nanoplasmonic sensor and gradient force generator. The combination of nanohole-enhanced dielectrophoresis, electroosmosis, and extraordinary optical transmission through the periodic gold nanohole array enables real-time label-free detection of analyte molecules in a 5 μL droplet using concentrations as low as 1 pM within a few minutes, which is more than 1000 times faster than purely diffusion-based binding. The nanohole-based optofluidic platform demonstrated here is straightforward to construct, applicable to both charged and neutral molecules, and performs a novel function that cannot be accomplished using conventional surface plasmon resonance sensors.