Biomimetic cell-membrane-camouflaged nanoparticles with desirable features have been widely used for various biomedical applications. However, the current research focuses on single cell membrane coating and using multiple cell membranes for nanoparticle functionalization is still challenging. In this work, platelet (PLT) and leukocyte (WBC) membranes are fused, PLT-WBC hybrid membranes are coated onto magnetic beads, and then their surface is modified with specific antibodies. The resulting PLT-WBC hybrid membrane-coated immunomagnetic beads (HM-IMBs) inherit enhanced cancer cell binding ability from PLTs and reduce homologous WBC interaction from WBCs, and are further used for highly efficient and highly specific isolation of circulating tumor cells (CTCs). By using spiked blood samples, it is found that, compared with commercial IMBs, the cell separation efficiency of HM-IMBs is improved to 91.77% from 66.68% and the cell purity is improved to 96.98% from 66.53%. Furthermore, by using the HM-IMBs, highly pure CTCs are successfully identified in 19 out of 20 clinical blood samples collected from breast cancer patients. Finally, the robustness of HM-IMBs is verified in downstream CTC analysis such as the detection of PIK3CA gene mutations. It is anticipated that this novel hybrid membrane coating strategy will open new possibilities for overcoming the limitations of current theranostic platforms.

In order to achieve reliable quantum-information processing results, we need to protect quantum gates along with the qubits from decoherence. Here we demonstrate experimentally on a nitrogen-vacancy system that by using a continuous-wave dynamical decoupling method, we might not only prolong the coherence time by about 20 times but also protect the quantum gates for the duration of the controlling time. This protocol shares the merits of retaining the superiority of prolonging the coherence time and at the same time easily combining with quantum logic tasks. This method can be useful in tasks where the duration of quantum controlling exceeds far beyond the dephasing time.

Under resonant conditions, a long sequence of landau-zener transitions can lead to Rabi oscillations. Using a nitrogen-vacancy (NV) center spin in diamond, we investigated the interference between more than 100 Landau-Zener processes. We observed the new type of Rabi oscillations of the electron spin resulting from the interference between successive Landau-Zener processes in various regimes, including both slow and fast passages. The combination of the control techniques and the favorable coherent properties of NV centers provides an excellent experimental platform to study a variety of quantum dynamical phenomena. The phenomenon of Rabi oscillations, first studied in 1937 [1], occurs in almost any quantum system under the influence of resonant external driving and is at the heart of various spectroscopic techniques. Landau-Zener (LZ) transitions, first studied in 1932 [2][3][4][5], are intriguing phenomena that are ubiquitous in quantum systems, typically occurring when two energy levels of a quantum system undergo an avoided crossing.Under suitable conditions LZ transitions can be treated as quantum coherent processes, and multiple such processes can interfere constructively or destructively [4]. Depending on the details of the interference, a long and regular sequence of LZ processes can exhibit resonance behavior similar to that seen in Rabi oscillations under weak driving conditions.The oscillations obtained in the case of constructive interference can therefore be seen as a manifestation of Rabi oscillations in the regime of ultrastrong driving [6]. Moreover, the interference between LZ processes gives rise to a number of novel features distinct from the case of weak driving. Particularly interesting is the fact that the patterns of the resonance lines vary drastically depending on whether each passage through the avoided crossing is slow or fast [6].The experimental observation of Rabi oscillations in the LZ regime requires stringent conditions. The coherence time of the quantum system is required to be long enough to allow the coherent interference between multiple LZ processes, and the control fields are required to be accurate and stable in order to precisely adjust the quantum phases that govern the interference effects. In addition, the time resolution of the measurement needs to be high enough to allow the monitoring of the dynamics on short timescales.With the recent advances in various quantum systems [7,8], a number of experiments were able to demonstrate the controlled interference of LZ transitions. Interference between two LZ transitions has been observed in gaseous molecules [9], semiconductor-based quantum dots [10], NV centers [11], and atoms in optical lattices [12]. Evidence for various interference effects involving multiple LZ transitions has been observed in the steady-state behavior of continuously driven superconducting qubits [13,14] and NV centers [15]. However, although those steady-state behaviors have been reported, the experimental observation of the abundant time-domain evolu...

Single molecular magnets (SMMs) are among the potential systems for quantum memory and quantum information processing. Quantum coherence and oscillation are critical for these applications. The ground-state quantum coherence and Rabi oscillations of the SMM V15 ([V15(IV)As6(III)O42(H2O)]6-) have been studied in this context. We have affirmatively measured at 2.4 K the Rabi quantum oscillations and coherence time T2 for the ground states of the V15 ion of collective spin S=1/2, in addition to confirming the previously reported results for the S=3/2 excited states. The oscillations of S=3/2 and S=1/2 states are of different frequencies, and so can be separately selected for purposive manipulations. T2 of 188±4  ns (S=3/2) and 149±10  ns (S=1/2) are much less than T1∼12  μs and are further extendible via various approaches for qubit implementations.

Precise control of an open quantum system is critical to quantum information processing, but is challenging due to inevitable interactions between the quantum system and the environment. We demonstrated experimentally at room temperature a type of dynamically corrected gates on the nitrogen-vacancy centers in diamond. The infidelity of quantum gates caused by environment nuclear spin bath is reduced from being the second-order to the sixth-order of the noise to control field ratio, which offers greater efficiency in reducing the infidelity by reducing the noise level. The decay time of the coherent oscillation driven by dynamically corrected gates is shown to be two orders of magnitude longer than the dephasing time, and is essentially limited by spin-lattice relaxation. The infidelity of DCG, which is actually constrained by the decay time, reaches 4 × 10 −3 at room temperature and is further reducible by 2-3 orders of magnitudes via lowering temperature. The greatly reduced noise dependence of infidelity and the uttermost extension of the coherent time mark an important step towards fault-tolerant quantum computation in realistic systems. Quantum information processing can provide a dramatic speed-up over classical computer for certain problems [1]. One of the most urgent demands in quantum computation is to realize noise-resistant universal quantum gates for qubits. Strategies including quantum error correction [2-4], decoherence-free subspace [5,6], and dynamical decoupling (DD) [7] have been developed to accomplish this task. Compared with the other two strategies, the resource requirements for the DD are modest [8], and no extra qubits is required. It uses stroboscopic qubit flips to average out the coupling to the environment.There are experiments to demonstrate DD as a successful technique in preventing the quantum states from being destroyed in open systems [9][10][11]. However, implementing DD in quantum gates is still of challenge, because in general the gate operation may not commute with the DD control. Recently, there are theoretical studies to address this problem via dynamically corrected gates (DCGs) [12][13][14][15], but experimental implementation is still elusive.Herein, we experimentally demonstrated a type of DCG, namely SUPCODE [14], in a single electron spin in diamond at room temperature. We experimentally verified that the SUPCODE reduces the error stemming from magnetic field fluctuation to the sixth-order of the fluctuation field to control field ratio, and largely diminishes the decoherence effect. The performance of quantum gate has been protected far beyond the quantum system's dephasing time T * 2 and is approximately limited by the spin-lattice relaxation time T 1 . Our successful demonstration of decoherece-protected universal quantum control is important for future quantum computations based on solid-state devices.The Hamiltonian describing a general single-qubit unitary operation on an electron-spin qubit in the rotating frame can be described as H C = ω 1 n · S, where 2 ] cos...

Universal sensing of the motion of mechanical resonators with high precision and low backaction is of paramount importance in ultraweak signal detection, which plays a fundamental role in modern physics. Here we present a universal scheme that mechanically transfers the motion of the resonator not directly measurable to the one that can be precisely measured using mechanical frequency conversion. Demonstration of the scheme at room temperature shows that both the motion imprecision and the backaction force are below the intrinsic level of the objective resonator, which agrees well with our theoretical prediction. The scheme developed here provides an effective interface between an arbitrary mechanical resonator and a high quantum efficient displacement sensor, and is expected to find extensive applications in highly demanding mechanical-based force measurements.

BackgroundCancer-associated fibroblasts (CAFs) are key factors in malignant tumor initiation, progression, and metastasis. However, the effect of CAFs autophagy on triple-negative breast cancer (TNBC) cells is not clear. In this study, the growth effect of TNBC cells regulated by CAFs autophagy was evaluated.Material/MethodsCAFs were obtained from invasive TNBC tumors and identified by Western blot and immunofluorescence staining assay. CAFs were co-cultured with TNBC cells, and migration and invasion were evaluated by Matrigel-coated Transwell and Transwell inserts. TNBC cells growth was detected by MTT assay, and epithelial-mesenchymal transition (EMT) regulated by CAFs was evaluated by Western blot assay.ResultsCAFs were identified by the high expression of α-smooth muscle actin (α-SMA) protein. Autophagy-relevant Beclin 1 and LC3-II/I protein conversion levels in CAFs were higher than those in NFs (P<0.05). TNBC cells migration, invasion, and proliferation levels were significantly improved in the CAFs-conditioned medium (CAFs-CM) group, compared with the other 3 groups (P<0.05). TNBC cells vimentin and N-cadherin protein levels were upregulated and E-cadherin protein level was downregulated in the CAFs-CM group compared with the control group (P<0.05). Further study indicated β-catenin and P-GSK-3β protein levels, which are the key proteins in the Wnt/β-catenin pathway, were upregulated in the CAFs-CM group compared with the control group (P<0.05).ConclusionsOur data demonstrated CAFs autophagy can enhance TNBC cell migration, invasion, and proliferation, and CAFs autophagy can induce TNBC cells to engage in the EMT process through the Wnt/β-catenin pathway.

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