Biomedical Engineering: Applications, Basis and Communications

The polysaccharide, mannan, has been shown to be an effective immunoprotective agent and vaccine adjuvant in a variety of bacterial and viral diseases in different animal species. The objective of this study was to evaluate the immune response of chickens after being intranasal (i.n.) immunized using the Newcastle disease virus (NDV) encapsulated in liposomes and coated with mannan. Groups of chickens were vaccinated once intranasally with virus alone, then with uncoated liposome-encapsulated NDV (NC-lip), or mannan-coated liposome-encapsulated NDV (Man-lip). On day 14, velogenic viral challenge was carried out on vaccinated chickens. Chickens receiving virus alone had a 20% survival rate. In contrast, groups that received Man-lip had a higher survival rate of 70% (P < 0.01). The titers of mucosal secretary immunoglobulin A (s-IgA) was the highest in the group for the birds that received Man-lip as mucosal adjuvant (P < 0.01). These results suggest that liposomes coated with mannan may thus be used as a potential adjuvant for mucosal vaccination against NDV. This is the first study in which mannan has been demonstrated to enhance an adaptive immune response against ND virus infection in chickens.

The endoscopy is a common diagnosis method for the detection of colorectal cancer and there are two methods to improve the diagnostic sensitivity. One is chromoendoscopy, and the other is magnifying endoscopy. Color contrast dye, such as indigo carmine, usually is sprayed on the surface of the intestine and can accumulate in the pits and crevices of the mucosa to enhance the identification of the lesion. However, this color contrast dye does not have target-specific and local-retention properties. For these reasons we encapsulated indigo carmine into chitosan nanoparticles (CNIC) by the ionic gelation to increase the retention time on intestine surface, and conjugated folic acid with chitosan nanoparticles (fCNIC) to target specifically adenomatous polyps. The size and zeta potential of CNIC and fCNIC measured by transmission electron microscope and zetasizer were both at the range of 120–140 nm and 20 mV respectively. The loading efficiency of indigo carmine in fCNIC was in the range of 60–70% and depended on the concentration of acetic acid solution used to dissolve chitosan and folic acid–chitosan conjugates and folic acid conjugation percentage. Bioassy results of fCNIC targeting to HT-29 colon cancer cells revealed that the prepared particle with high folic acid conjugation had a better adhesion effect. These results implied that fCNIC with high folic acid conjugation could serve as an ideal vector for a colon-specific targeting system. According to this concept, we designed a novel detection system to enhance the accuracy of endoscopic diagnosis for colorectal cancer.

In the present study, linear orthogonal projection algorithms (least square sense linear mapping (LSLM), minimum variance estimation (MVE), spectral domain estimation (SDC) and time domain constraint (TDC)) have been applied to reduce the background EEG noise on small number of trials elicited by auditory stimuli. These methods are compared to each other with respect to eigendecomposition based spectral signal-to-noise-ratio (SSNR) in tests where the grand average of experimental observations is considered as the template evoked potential (EP) signal. The actual ongoing EEG series and single-sweep EP are summed in pseudosimulations. The LSLM having simplest formulation is found to be most useful pre-filter among those methods in removing large amount of the noise without loss of information about EP components since both EEG noise level and EP component variations are highly correlated with eigenspectra of the raw data.

The interfacial characteristics of self-assembled monolayer (SAM), that are applied in miniaturized sensor design, were strongly influenced by the SAM constitution. The electrochemical and interfacial characteristics of hybrid SAMs that constituted with ferrocenyl octanethiol (FcC₈SH) and unsubstituted octanethiol (C₈) or 2-mercaptopyrimidine (2-MPD) were investigated in this study. The peaks of anodic oxidation were observed at around 0.49 V (vs. Ag/AgCl) in the FcC₈SH/C₈ hybrid SAM. However, the oxidation potentials descended from 0.42–0.38 V as the molar fraction of FcC₈SH was decreased from 0.8–0.2 in the FcC₈SH/2-MPD hybrid SAM. On the other hand, the interfacial hydrophilicity of FcC₈SH/2-MPD hybrid SAM was measured to be higher than the FcC₈SH/C₈ hybrid SAM due to the random arrangement of SAM caused by the shape of 2-MPD. Then, the surface roughness of hybrid SAM and chain length of ferrocenyl alkanethiols were all considered to be the parameters of interfacial characteristics.

In summary, doping of 2-MPD in SAMs might reduce the rigidity of ferrocenyl alkanethiol SAMs and increase the interfacial hydrophilicity. This result will be useful in the development of the low power consumption portable bioanalytical system. And a miniaturized bioanalytical system based on ferrocenyl SAMs would be developed in the future.

With the advancement of nanotechnology, nano-sized bioceramics have been dedicated much attention to biomedical applications in the past decades. In this study, the magnetic-hydroxyapatite nanoparticles (mHap NPs) were synthesized and magnetized by the addition of irons into hydroxyapatite using precipitation process. The mHap NPs were with good biocompatibility and superparamagnetic property which would have great promise in biological applications. We have evaluated the essential properties including plasmid DNA (pDNA) binding capacity by electrophoresis, qualitative transfection efficiency by fluorescence microscopy and quantitative GDNF expression by enzyme-link immunosorbent assay (ELISA). The results indicated that mHap NPs could be successfully binding with pDNA to form pDNA-mHap NPs transfection complex. The endocytosis of pDNA-mHap NPs transfection complex was mediated into cells and facilitated if magnetic field was applied. The transfection efficiency could also be significantly improved by magnetofection. The gene expression had been four-fold increase in high pDNA loading (2 μg/well) in transfection procedure with magnetic field compared with traditional transfection method. In brief, the mHap NPs have great potential as non-viral inorganic delivery carriers for gene delivery system.

Total Knee Arthroplasty (TKA) using standard artificial knee implant has a limitation in restriction in the range of motion and freedom of movements'. This study was worked out to compare the kinematics of a reconstructed 3D knee with standard and high flexion artificial knee designs. A CT bone model reconstructed with MIMICS for a 3D normal knee joint and the simulation was done for normal knee, standard version of artificial knee as well as the high flexion knee designs. The results of the analyses, provides us an insight that high flexion designs were most suited and gives increased range of motion and also provides an additional degree of freedom so that it almost mimics the normal knee movement.

The high flexion design when tested under simulated environment provided a better functionality and increased movements. It was concluded that the normal knee has 6 degrees of freedom (DOF); the standard version has 1 rotation and 1 translation. The high flexion design provides 2 rotations and 1 translation.

The gene sequences BLAST and its alignment is the common and important step in biological discovery. Basically speaking, BLAST technique is already a mature and well-known to biological scientists, but aiming at specific organisms is seldom seen in world-wide databases. In this study, we develop a web-based organism specific BLAST search engine to replenish researchers' use. This study constructed a web service, the Organism Specific Search Engine, for taxonomy scientists and all users concerned. This service provides most common specific organism BLAST, scoring system and GUI (Graphical User Interface) for users. On the other hand, researchers can clearly and concisely get the results from E-mail service in order to avoid waiting for a long time. The Organism Specific Search Engine evaluate the similarities between two or more nucleotide or protein sequences against a specific organism, which can help researchers realize the differences between one chosen organism rapidly. Users can apply this information more easily and directly than taking from NCBI or other famous database system. Furthermore, this system will update its database from NCBI website automatically, which can catch up its new and correct databases. Notably, the website is freely available at .

High failure rates are expected in the treatment of osteoporotic proximal femoral fractures. A newly designed femoral neck locking dynamic hip screw has been developed to increase the fixation strength; a biomechanical examination was performed to prove its efficacy.

Femoral surrogate specimens were used for the test. Unstable intertrochanteric fractures were created on specimens. Then these specimens were divided into two groups to test two different methods of fixation: (1) the conventional dynamic hip screw and (2) the new designed femoral neck fixation dynamic hip screw. For each specimen, the peak cyclic loading was 800 N, and a total of 20,000 cycles were applied. The vertical displacement, rotation around the long axis of lag screw, and the varus rotation around the center of femoral head between the two groups were compared at specific intervals.

All the conventional dynamic hip screw constructs failed within 1000 cycles, while no gross mechanical failure was recorded for the femoral neck fixation dynamic hip construct even after 20,000 loading cycles. The mechanical test comparing the two constructs at the end of each 1000 loading cycles demonstrated that the femoral neck fixation dynamic hip screw construct is stronger than that of the conventional dynamic hip screw.

For the fixation of proximal femoral fractures, the femoral neck fixation dynamic hip screw can provide a stronger support than what a conventional dynamic hip screw can do. At the same time, femoral neck can be a suitable site for the application of proximal locking screws.

Electrophysiological correlates of human reliability in visual response tasks were investigated in 16 healthy subjects using electroencephalographic (EEG) spectral power and event-related potentials (ERP). Human reliability was first determined by calculating individual reaction accuracy in order to split the entire group into high reliability (HR) and low reliability (LR) subgroups, each with eight subjects. The EEG activities of testing subjects were measured at rest condition for 5 min, and during a modified Eriksen flanker task. Artifact-free EEG segments were used to compute the distribution of EEG at varied frequency bands as well as to detect peak and latency of ERPs of the flanker task. Our results showed that subjects with LR exhibited higher alpha band EEG power at the frontal recording site. Additionally, LR group revealed lower P300 amplitude and predominantly longer P300 latency at centro-parietal recording site than those of the HR group. These findings implied that higher alpha band EEG power at frontal and smaller amplitude, longer latency P300 component of ERP measures at centro-parietal might reveal the trait of lower reliability in healthy controls during visual tasks.

Antiangiogenic gene therapy is a promising approach to inhibit neovascularization via angiogenesis, the growth of new blood vessels from pre-existing ones. In recent years, hepatocellular carcinoma (HCC) is considered as one of the suitable targets for antiangiogenic approaches due to its high neovascularization. On the other hand, ultrasound (US) is believed to be a novel and effective tool to locally deliver gene into target tumors. US can temporarily change the permeability of cell membrane and thus enhance the delivery of naked DNA into cells. In this study, the efficiency of gene transfection in tumor was compared by changing the US contrast agent (UCA) concentration and sonication time. Luciferase and enhanced green fluorescent protein (EGFP) plasmids mixed with SonoVue^® were injected intratumorally (IT), and US was applied at 20% duty cycle and 2 W/cm² in intensity. Finally, the efficacy of employing US to deliver genes encoded with an antiangiogenic factor, endostatin (ED), to suppress the growth of a preclinical HCC, which was inoculated subcutaneous (SC) tumor model, is evaluated. Our results show that weekly intratumoral injection group led to a 74% inhibition in HCC growth. In summary, the present study revealed the efficacy of US as a nonviral technology to efficiently deliver genes to tumors by weekly IT treatment approach, and to deliver angiogenic inhibitors to HCC in particular.