This review presents an overview of “Lab on Fiber” technologies and devices with special focus on the design and development of advanced fiber optic nanoprobes for biological applications. Depending ...on the specific location where functional materials at micro and nanoscale are integrated, “Lab on Fiber Technology” is classified into three main paradigms: Lab on Tip (where functional materials are integrated onto the optical fiber tip), Lab around Fiber (where functional materials are integrated on the outer surface of optical fibers), and Lab in Fiber (where functional materials are integrated within the holey structure of specialty optical fibers).
This work reviews the strategies, the main achievements and related devices developed in the “Lab on Fiber” roadmap, discussing perspectives and challenges that lie ahead, with special focus on biological sensing applications.
The Lab on Fiber Technology arises from the judicious synergy of forefront Key Enabling Technologies such as Photonics and Nanotechnology. This work reviews the strategies, the main achievements and related devices developed in the “Lab on Fiber” roadmap, by classifying this paradigm according to the specific location where functional materials are integrated, in Lab on Tip, Lab around Fiber and Lab in Fiber.
The integration of microfluidics and photonic biosensors has allowed achievement of several laboratory functions in a single chip, leading to the development of photonic lab-on-a-chip technology. ...Although a lot of progress has been made to implement such sensors in small and easy-to-use systems, many applications such as point-of-care diagnostics and in vivo biosensing still require a sensor probe able to perform measurements at precise locations that are often hard to reach. The intrinsic property of optical fibers to conduct light to a remote location makes them an ideal platform to meet this demand. The motivation to combine the good performance of photonic biosensors on chips with the unique advantages of optical fibers has thus led to the development of the so-called lab-on-fiber technology. This emerging technology envisages the integration of functionalized materials on micro- and nano-scales (i.e. the labs) with optical fibers to realize miniaturized and advanced all-in-fiber probes, especially useful for (but not limited to) label-free chemical and biological applications. This review presents a broad overview of lab-on-fiber biosensors, with particular reference to lab-on-tip platforms, where the labs are integrated on the optical fiber facet. Light-matter interaction on the fiber tip is achieved through the integration of thin layers of nanoparticles or nanostructures supporting resonant modes, both plasmonic and photonic, highly sensitive to local modifications of the surrounding environment. According to the physical principle that is exploited, different configurations - such as localized plasmon resonance probes, surface enhanced Raman scattering probes and photonic probes - are classified, while various applications are presented in context throughout. For each device, the surface chemistry and the related functionalization protocols are reviewed. Moreover, the implementation strategies and fabrication processes, either based on bottom-up or top-down approaches, are discussed. In conclusion we highlight some of the further development opportunities, including lab-in-a-needle technology, which could have a direct and disruptive impact in localized cancer treatment applications.
Background
The incidence of de novo gastroesophageal reflux disease (GERD) after LSG is substantial. However, an objective correlation with the structural gastric and EGJ changes has not been ...demonstrated yet. We aimed to prospectively evaluate the effects of laparoscopic sleeve gastrectomy (LSG) on the structure and function of the esophagogastric junction (EGJ) and stomach.
Methods
Investigations were performed before and after > 50% reduction in excess body weight (6–12 months after LSG). Subjects with GERD at baseline were excluded. Magnetic Resonance Imaging (MRI), high-resolution manometry (HRM), and ambulatory pH-impedance measurements were used to assess the structure and function of the EGJ and stomach before and after LSG.
Results
From 35 patients screened, 23 (66%) completed the study (age 36 ± 10 years, BMI 42 ± 5 kg/m
2
). Mean excess weight loss was 59 ± 18% after 7.1 ± 1.7-month follow-up. Esophageal acid exposure (2.4 (1.5–3.2) to 5.1 (2.8–7.3);
p
= 0.040 (normal < 4.0%)) and reflux events increased after surgery (57 ± 24 to 84 ± 38;
p
= 0.006 (normal < 80/day)). Esophageal motility was not altered by surgery; however, intrabdominal EGJ length and pressure were reduced (both
p
< 0.001); whereas the esophagogastric insertion angle (35° ± 11° to 51° ± 16°;
p
= 0.0004 (normal < 60°)) and esophageal opening diameter (16.9 ± 2.8 mm to 18.0 ± 3.7 mm;
p
= 0.029) were increased. The increase in reflux events correlated with changes in EGJ insertion angle (
p
= 0.010). Patients with > 80% reduction in gastric capacity (TGV) had the highest prevalence of symptomatic GERD.
Conclusion
LSG has multiple effects on the EGJ and stomach that facilitate reflux. In particular, EGJ disruption as indicated by increased (more obtuse) esophagogastric insertion angle and small gastric capacity were associated with the risk of GERD after LSG.
clinicaltrials.gov
:
NCT01980420
Background
The aim of this study is to compare surgical outcomes including postoperative complications and prognosis between total gastrectomy (TG) and proximal gastrectomy (PG) for proximal gastric ...cancer (GC). Propensity-score-matching analysis was performed to overcome patient selection bias between the two surgical techniques.
Methods
Among 457 patients who were diagnosed with GC between January 1990 and December 2010 from four Italian institutions, 91 underwent PG and 366 underwent TG. Clinicopathologic features, postoperative complications, and survivals were reviewed and compared between these two groups retrospectively.
Results
After propensity-score matching had been done, 150 patients (75 TG patients, 75 PG patients) were included in the analysis. The PG group had smaller tumors, shorter resection margins, and smaller numbers of retrieved lymph nodes than the TG group. N stages and 5-year survival rates were similar after TG and PG. Postoperative complication rates after PG and TG were 25.3 and 28%, respectively, (
P
= 0.084). Rates of reflux esophagitis and anastomotic stricture were 12 and 6.6% after PG and 2.6 and 1.3% after TG, respectively (
P
<
0.001 and
P
= 0.002). 5-year overall survival for PG and TG group was 56.7 and 46.5%, respectively (
P
= 0.07). Survival rates according to the tumor stage were not different between the groups. Multivariate analysis showed that type of resection was not an independent prognostic factor.
Conclusion
Although PG for upper third GC showed good results in terms of survival, it is associated with an increased mortality rate and a higher risk of reflux esophagitis and anastomotic stricture.
Background
Laparoscopic sleeve gastrectomy (LSG) is currently the most commonly performed bariatric procedure. Endoscopic sleeve gastroplasty (ESG) is a promising new bariatric technique which is ...less invasive in its approach. To date no study has compared quality of life (QoL) outcomes between LSG and ESG. The aim of this study is to compare QoL after ESG and LSG using a propensity score analysis.
Methods
QoL was evaluated by means of Gastrointestinal Quality of Life Index (GIQLI) questionnaire before and 6 months after the procedure. Patients were matched for age, sex, preoperative weight, and comorbidities.
Results
Propensity score matching resulted in 23 pairs of patients homogeneous for age (
p
= 0.3), preoperative BMI (
p
= 0.3), sex (
p
= 0.74), and comorbidities (
p
= 0.9). Post-ESG patients, despite a less important %EWL (39.9 (17.5–58.9)vs 54.9 (46.2–65);
p
= 0.01) and %TWL (13.4 (7.8–20.9) vs 18.8 (17.6–21.8);
p
= 0.03), presented better QoL (14 3–24 vs 13 (− 1–23) ΔGIQLI score;
p
= 0.79) with clear advantage for the gastrointestinal symptoms subdomain (66.5 (61–70.5) vs 59 (55–63);
p
= 0.001), while post-LSG patients presented a worsening of GERD symptoms (30.7% vs 0%) and an increased use of PPI therapy (
p
= 0.004). Resolution or improvement of comorbidities was similar (ESG 53% vs LSG 45.8%;
p
= 0.79) in both groups.
Conclusion
LSG may significantly affect QoL and results in worsening of gastrointestinal symptoms including GERD. ESG is a promising less invasive bariatric endoscopic procedure that demonstrated a positive impact on both QoL and comorbidities, which could lead to greater patient acceptance earlier in their disease or at a younger age.
In this paper we report on the engineering of repeatable surface enhanced Raman scattering (SERS) optical fiber sensor devices (optrodes), as realized through nanosphere lithography. The Lab-on-Fiber ...SERS optrode consists of polystyrene nanospheres in a close-packed arrays configuration covered by a thin film of gold on the optical fiber tip. The SERS surfaces were fabricated by using a nanosphere lithography approach that is already demonstrated as able to produce highly repeatable patterns on the fiber tip. In order to engineer and optimize the SERS probes, we first evaluated and compared the SERS performances in terms of Enhancement Factor (EF) pertaining to different patterns with different nanosphere diameters and gold thicknesses. To this aim, the EF of SERS surfaces with a pitch of 500, 750 and 1000 nm, and gold films of 20, 30 and 40 nm have been retrieved, adopting the SERS signal of a monolayer of biphenyl-4-thiol (BPT) as a reliable benchmark. The analysis allowed us to identify of the most promising SERS platform: for the samples with nanospheres diameter of 500 nm and gold thickness of 30 nm, we measured values of EF of 4 × 10⁵, which is comparable with state-of-the-art SERS EF achievable with highly performing colloidal gold nanoparticles. The reproducibility of the SERS enhancement was thoroughly evaluated. In particular, the SERS intensity revealed intra-sample (i.e., between different spatial regions of a selected substrate) and inter-sample (i.e., between regions of different substrates) repeatability, with a relative standard deviation lower than 9 and 15%, respectively. Finally, in order to determine the most suitable optical fiber probe, in terms of excitation/collection efficiency and Raman background, we selected several commercially available optical fibers and tested them with a BPT solution used as benchmark. A fiber probe with a pure silica core of 200 µm diameter and high numerical aperture (i.e., 0.5) was found to be the most promising fiber platform, providing the best trade-off between high excitation/collection efficiency and low background. This work, thus, poses the basis for realizing reproducible and engineered Lab-on-Fiber SERS optrodes for in-situ trace detection directed toward highly advanced in vivo sensing.
Background
This prospective study applied magnetic resonance imaging (MRI) to assess the effect of laparoscopic sleeve gastrectomy (LSG) on gastric structure and function. The impact of these changes ...on patient outcomes was analyzed.
Method
Obese patients without gastrointestinal symptoms referred for bariatric surgery were recruited prospectively. Pre-operative assessment included (i) high-resolution manometry and pH-impedance monitoring and (ii) magnetic resonance imaging (MRI) measurement of gastric capacity, accommodation, and emptying with the 400 ml liquid Nottingham test meal (NTM). Studies were repeated 6–7 months after LSG. Weight loss and changes in the Gastrointestinal Quality of Life Index (GIQLI) assessed patient outcomes.
Results
From 35 patients screened, 23 (66%) completed the study (17 females, age 36 ± 10 years, BMI 42 ± 5 kg/m2). Mean excess weight loss was 59 ± 18% at follow-up. Total gastric volume (capacity) after the meal was 467 mL (455–585 ml) before and 139 mL (121–185 ml) after LSG (normal reference 534 (419–675) mL), representing a mean 70% reduction (
p
< 0.0001). Similar findings were present for gastric content volume indicating rapid early-phase gastric emptying (GE) post-LSG. Conversely, late-phase GE was slower post-LSG (2.5 ± 1.0 vs. 1.4 ± 0.6 mL/min;
p
< 0.0001; (reference
1
.5(1.4–4.9) mL/min)). Patients with ≥ 80% reduction in gastric capacity had greater weight loss (
p
= 0.008), but worse gastrointestinal outcomes (
p
= 0.023).
Conclusions
MRI studies quantified the marked reduction in gastric capacity after LSG. The reduction in capacity was associated with rapid early- but slow late-phase GE after surgery. These changes were associated with weight loss; however, reductions in gastric capacity ≥ 80% were linked to increased acid reflux and impacted on gastrointestinal quality of life.
Virtual reality (VR) and augmented reality (AR) in complex surgery are evolving technologies enabling improved preoperative planning and intraoperative navigation. The basis of these technologies is ...a computer-based generation of a patient-specific 3-dimensional model from Digital Imaging and Communications in Medicine (DICOM) data. This article provides a state-of-the- art overview on the clinical use of this technology with a specific focus on hepatic surgery. Although VR and AR are still in an evolving stage with only some clinical application today, these technologies have the potential to become a key factor in improving preoperative and intraoperative decision making.
Laser-induced thermotherapy has shown promising potential for the treatment of unresectable primary pancreatic ductal adenocarcinoma tumors. Nevertheless, heterogeneous tumor environment and complex ...thermal interaction phenomena that are established under hyperthermic conditions can lead to under/over estimation of laser thermotherapy efficacy. Using numerical modeling, this paper presents an optimized laser setting for Nd:YAG laser delivered by a bare optical fiber (300 µm in diameter) at 1064 nm working in continuous mode within a power range of 2-10 W. For the thermal analysis, patient-specific 3D models were used, consisting of tumors in different portions of the pancreas. The optimized laser power and time for ablating the tumor completely and producing thermal toxic effects on the possible residual tumor cells beyond the tumor margins were found to be 5 W for 550 s, 7 W for 550 s, and 8 W for 550 s for the pancreatic tail, body, and head tumors, respectively. Based on the results, during the laser irradiation at the optimized doses, thermal injury was not evident either in the 15 mm lateral distances from the optical fiber or in the nearby healthy organs. The present computational-based predictions are also in line with the previous ex vivo and in vivo studies, hence, they can assist in the estimation of the therapeutic outcome of laser ablation for pancreatic neoplasms prior to clinical trials.
Pancreatic islet isolation is critical for type 2 diabetes research. Although -omics approaches have shed light on islet molecular profiles, inconsistencies persist; on the other hand, functional ...studies are essential, but they require reliable and standardized isolation methods. Here, we propose a simplified protocol applied to very small-sized samples collected from partially pancreatectomized living donors. Islet isolation was performed by digesting tissue specimens collected during surgery within a collagenase P solution, followed by a Lympholyte density gradient separation; finally, functional assays and staining with dithizone were carried out. Isolated pancreatic islets exhibited functional responses to glucose and arginine stimulation mirroring donors’ metabolic profiles, with insulin secretion significantly decreasing in diabetic islets compared to non-diabetic islets; conversely, proinsulin secretion showed an increasing trend from non-diabetic to diabetic islets. This novel islet isolation method from living patients undergoing partial pancreatectomy offers a valuable opportunity for targeted study of islet physiology, with the primary advantage of being time-effective and successfully preserving islet viability and functionality. It enables the generation of islet preparations that closely reflect donors’ clinical profiles, simplifying the isolation process and eliminating the need for a Ricordi chamber. Thus, this method holds promises for advancing our understanding of diabetes and for new personalized pharmacological approaches.
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